WO2024243339A2 - Boldine to reduce muscle atrophy and promote neuromuscular recovery - Google Patents

Abstract

Provided are methods of treating and preventing peripheral nerve injuries and denervation-induced muscular atrophy (e.g., denervation-induced muscular atrophy due to trauma, autoimmune disorders, or viral infections) using boldine or derivatives or pharmaceutically acceptable salts thereof. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.

Description

Attorney Docket No.37759.0543P1 BOLDINE TO REDUCE MUSCLE ATROPHY AND PROMOTE NEUROMUSCULAR RECOVERY CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Application No.63/468,473, filed on May 23, 2023, the contents of which are hereby incorporated by reference in their entirety. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH [0002] This invention was made with government support under Grant Nos. I01-BX003748, awarded by the Department of Veterans Affairs (VA), TL1-TR001880, T90-DE030854, R44- NS108869, and R01-NS117757, awarded by the National Institutes of Health (NIH), SCIRP SC170315, awarded by the Department of Defense, and B-2020-C, awarded by the VA Rehabilitation Research and Development. The government has certain rights in the invention. BACKGROUND [0003] Peripheral nerve injury (PNI) routinely presents in approximately 3-5% of all trauma cases and may result in significant sensorimotor deficits and diminished quality of life (L. R. Robinson, Muscle Nerve 23, 863-873 (2000) and G. R. Evans, Anat Rec 263, 396-404 (2001)). Unfortunately, only approximately 50% of patients report satisfactory functional recovery after PNI, despite state-of-the-art surgical intervention (B. J. Pfister, et. al., Crit Rev Biomed Eng 39, 81-124 (2011) and A. C. Ruijs, et. al., Plast Reconstr Surg 116, 484-494; discussion 495-486 (2005)). Severe nerve injuries – most often associated with poor recovery – are denoted by axonal disconnection within the nerve sheath, effectively severing communication between the neuronal cell body (residing within or adjacent to the spinal cord) and its distal end target (e.g., muscle/sensory end organ) (B. J. Pfister, et. al., Crit Rev Biomed Eng 39, 81-124 (2011)). Such injuries initiate a series of choreographed degenerative and pro-regenerative processes; for instance, distal axon segments undergo Wallerian degeneration, denervated muscle upregulates acetylcholine receptor expression, and denervated Schwann cells form the bands of Bungner to create a pro-regenerative environment that facilitates axonal regeneration and muscle Attorney Docket No.37759.0543P1 reinnervation (S. Y. Fu, et. al., J Neurosci 15, 3886-3895 (1995) and S. Y. Fu, et. al., J Neurosci 15, 3876-3885 (1995)). In particular, axonal degeneration results in the loss of acetylcholine release followed by nicotinic acetylcholine receptor (AChR)-mediated muscle depolarization and muscarinic AChR-mediated activation of terminal Schwann cells, which initially serve to guide regenerating motor axons to neuromuscular junctions (Y. Sugiura, et. al., Biosci Rep 31, 295-302 (2011), C. P. Ko, et. al., Cold Spring Harb Perspect Biol 7, a020503 (2015) and D. Arbour, et. al., J Physiol 595, 647-661 (2017)). However, extended periods without axonal contact leads to the gradual degradation of this pro-regenerative environment and irrevocable muscle atrophy (S. Y. Fu, et. al., J Neurosci 15, 3886-3895 (1995) and S. Y. Fu, et. al., J Neurosci 15, 3876-3885 (1995)). Indeed, denervation impairs muscle membrane organization and reduces the stability of the neuromuscular junction by increasing nAChR degradation over nAChR turnover (S. Strack, et. al., J Muscle Res Cell Motil 36, 517-524 (2015)). Also, the regenerative capacity of initially pro-regenerative Schwann cells fades over time, resulting in dissolution of the bands of Bungner and ultimately Schwann cell apoptosis (J. A. Gomez-Sanchez, et. al., J Neurosci 37, 9086-9099 (2017)). Therefore, successful reinnervation requires re-integration of the regenerating axons and denervated target muscle before the loss of the regenerative pathway and irrevocable atrophy minimize the likelihood of meaningful recovery. [0004] Connexins are cytoplasmic membrane proteins named based on their molecular weights. Connexins assemble as hexamers (connexons) which are non-selective pores through which small molecules can pass. Connexons are the building blocks of gap junctions which electrically and chemically couple cells in the heart, nervous system and elsewhere, or as hemichannels (HC) which allow communication between the cytoplasm and extracellular space. These HC are involved in some physiological processes, such as release of prostaglandin E from osteocytes, and have been implicated in a growing number of pathological conditions that include expansion of secondary injury after a spinal cord injury (Chen, M.J., et al., Glia, 2012. 60(11): p.1660-70) and skeletal muscle atrophy caused by nerve transection (Cea, L.A., et al., Proc Natl Acad Sci U S A, 2013.110(40): p.16229-16234 and Cisterna, B.A., et al., Nat Commun, 2020.11(1): p.1073). Connexin hemichannels are not expressed on the cytoplasmic membrane of skeletal muscle fibers (sarcolemma) unless muscle is stressed by some insult such as loss of innervation by lower motor neurons (Chen, M.J., et al., Glia, 2012.60(11): p.1660-70) and skeletal muscle atrophy caused by nerve transection (Cea, L.A., et al., Proc Natl Acad Sci U Attorney Docket No.37759.0543P1 S A, 2013.110(40): p.16229-16234 and Cisterna, B.A., et al., Nat Commun, 2020.11(1): p. 1073). [0005] Denervated muscle fibers remain viable after injury but undergo extensive atrophy, which is associated with de novo expression of connexin (Cx) hemichannels (HC) 43 and 45 within the cytoplasmic membrane of skeletal muscle fibers (sarcolemma) (L. A. Cea, et. al., Proc Natl Acad Sci U S A 110, 16229-16234 (2013)). In the sarcolemma, Cx HC cause physiological changes, such as increased permeability of the sarcolemma to calcium, ATP and other small molecules, reduced resting membrane potential and activation of muscle atrophy programs (L. A. Cea, et. al., Proc Natl Acad Sci U S A 110, 16229-16234 (2013) and B. A. Cisterna, et. al., Biochim Biophys Acta 1862, 2168-2176 (2016)). Recently, Cx HC formation in denervated muscle has been reported to inhibit axon growth and muscle integration in vitro (B. A. Cisterna, et. al., Nat Commun 11, 1073 (2020)). Based on these findings, inhibiting Cx HC formation may be a potential therapeutic target following PNI. [0006] Though strides have been made toward addressing complications of nervous system injuries, there is no cell-based or pharmacologic approach to consistently improve sensory or motor function after a traumatic injury to the nervous system. Thus, there is a significant clinical need to develop methods of treating and preventing peripheral nerve injuries and denervation- induced muscular atrophy that can develop therefrom. These needs and others are met by the following disclosure. SUMMARY [0007] In accordance with the purpose(s) of the invention, as embodied and broadly described herein, the invention, in one aspect, relates to methods of preventing or treating peripheral nerve injuries and denervation-induced muscular atrophy including, but not limited to, denervation-induced muscular atrophy that is a result of trauma, an autoimmune disorder, or a viral infection, via administration of boldine or an analog thereof. [0008] Thus, disclosed are methods of treating and/or preventing a peripheral nerve injury in a subject in need thereof, the method comprising administering to the subject an effective amount of a compound having a structure represented by a formula: Attorney Docket No.37759.0543P1 , wherein R¹ is selected from ²

R is selected from hydrogen, halogen, –CN, –NH2, –OH, –NO2, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1- C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl; wherein each of R³ and R⁴ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1- C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl, or wherein R³ and R⁴ join together to form a ring having 5-7 atoms; wherein each of R⁵ and R⁶ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl, or wherein R⁵ and R⁶ join together to form a ring having 5-7 atoms; and wherein R⁷ is selected from hydrogen, halogen, –CN, –NH2, –OH, –NO2, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1- C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1- C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl, or a pharmaceutically acceptable salt thereof. [0009] Also disclosed are methods of treating and/or preventing denervation-induced muscular atrophy in a subject in need thereof, the method comprising administering to the subject an effective amount of a compound having a structure represented by a formula: ,

[0010] wherein R¹ is selected from hydrogen and C1-C4 alkyl; wherein R² is selected from hydrogen, halogen, –CN, –NH2, –OH, –NO2, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1- C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1- Attorney Docket No.37759.0543P1 C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl; wherein each of R³ and R⁴ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1- C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl, or wherein R³ and R⁴ join together to form a ring having 5-7 atoms; wherein each of R⁵ and R⁶ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl, or wherein R⁵ and R⁶ join together to form a ring having 5-7 atoms; and wherein R⁷ is selected from hydrogen, halogen, –CN, –NH2, –OH, –NO2, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1- C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1- C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl, or a pharmaceutically acceptable salt thereof. [0011] While aspects of the present invention can be described and claimed in a particular statutory class, such as the system statutory class, this is for convenience only and one of skill in the art will understand that each aspect of the present invention can be described and claimed in any statutory class. Unless otherwise expressly stated, it is in no way intended that any method or aspect set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not specifically state in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, or the number or type of aspects described in the specification. BRIEF DESCRIPTION OF THE DRAWINGS [0012] The above and other objects, features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments thereof with reference to the accompanying drawings. [0013] FIG.1 shows a representative illustration of an experimental timeline. [0014] FIG.2A and FIG.2B show representative data illustrating that oral administration of boldine preserves evoked muscle response following axotomy. Attorney Docket No.37759.0543P1 [0015] FIG.3A-D show representative data illustrating denervated tibialis anterior muscle weight. [0016] FIG.4A-D show representative data illustrating Cx43 and Cx45 expression in denervated muscle at 4 weeks following axotomy. [0017] FIG.5A-D show representative data illustrating denervated muscle fiber size histograms at 4 weeks following axotomy. [0018] FIG.6A and FIG.6B show representative data illustrating denervated Schwann cell co-expression with Cx43 at 4 weeks post axotomy. [0019] FIG.7A and FIG.7B show representative data illustrating evoked muscle response at 4 and 6 weeks following delayed repair. [0020] FIG.8A and FIG.8B show representative data illustrating compound muscle action potential at 6 weeks following delayed repair. [0021] FIG.9A and FIG.9B show representative data illustrating compound nerve action potentials at 6 weeks following delayed repair. [0022] FIG.10A and FIG.10B show representative data illustrating nerve morphometry at 6 weeks following delayed repair. [0023] FIG.11A-D show representative data illustrating reinnervated muscle fiber size histograms at 6 weeks following delayed repair. [0024] FIG.12A-D show representative data illustrating acetylcholine receptor expression and neuromuscular junction formation at 6 weeks following delayed repair. [0025] FIG.13A-D show representative data illustrating acetylcholine receptor expression and neuromuscular junction formation at 6 weeks following delayed repair. [0026] FIG.14 shows representing data illustrating force-frequency measurements performed at 14 days after complete spinal cord transection at T9 using EDL muscle by ex-vivo physiological testing. [0027] FIG.15A and FIG.15B show representative data illustrating physical function of mice with double knockouts of Cx43/45 in muscle cells and genotype controls after 65 kdyne contusion SCI or laminectomy. FIG.15A illustrates data summarized for males. FIG.15B illustrates data summarized for females. Attorney Docket No.37759.0543P1 [0028] FIG.16A and FIG.16B show representative data illustrating the effect of a Cx43/45 double cKO on metabolic cage parameters. FIG.16A illustrates the amount decline in oxygen consumption. FIG.16B illustrates the amount caloric expenditure that occurred after SCI. [0029] FIG.17A-D show representative data illustrating acetylcholine receptor expression and neuromuscular junction formation at 6 weeks following delayed repair. [0030] FIG.18 shows representative data illustrating heat map of relative levels of selected metabolites in serum from spinal cord transected mice treated with vehicle (SCIv) or boldine (SCIb). [0031] FIG.19 shows representative data illustrating neurofilament expression in distal nerve stump at 4 weeks post injury. [0032] Additional advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or can be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. DETAILED DESCRIPTION [0033] The present invention can be understood more readily by reference to the following detailed description of the invention and the Examples included therein. [0034] Disclosed are components that can be used to perform the disclosed methods and systems. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these components are disclosed that while specific reference of each various individual and collective combinations and permutation of these may not be explicitly disclosed, each is specifically contemplated and described herein, for all methods and systems. This applies to all aspects of this application including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific embodiment or combination of embodiments of the disclosed methods. [0035] The present methods may be understood more readily by reference to the following detailed description of preferred embodiments and the examples included therein. Attorney Docket No.37759.0543P1 [0036] While aspects of this disclosure can be described and claimed in a particular statutory class, such as the system statutory class, this is for convenience only and one of skill in the art will understand that each aspect of this disclosure can be described and claimed in any statutory class. Unless otherwise expressly stated, it is in no way intended that any method or aspect set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not specifically state in the claims or description that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, or the number or type of aspects described in the specification. [0037] Throughout this application, various publications are referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this pertains. The references disclosed are also individually and specifically incorporated by reference herein for the material contained in them that is discussed in the sentence in which the reference is relied upon. Nothing herein is to be construed as an admission that the present application is not entitled to antedate such publication by virtue of prior invention. Further, stated publication dates may be different from actual publication dates, which can require independent confirmation. A. DEFINITIONS [0038] Listed below are definitions of various terms used to describe this invention. These definitions apply to the terms as they are used throughout this specification, unless otherwise limited in specific instances, either individually or as part of a larger group. [0039] As used in the specification and in the claims, the term “comprising” can include the aspects “consisting of” and “consisting essentially of.” [0040] As used in the specification and claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. [0041] Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed Attorney Docket No.37759.0543P1 as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as “about” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “about 10” is also disclosed. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed. [0042] As used herein, the terms “about” and “at or about” mean that the amount or value in question can be the value designated some other value approximately or about the same. It is generally understood, as used herein, that it is the nominal value indicated ±10% variation unless otherwise indicated or inferred. The term is intended to convey that similar values promote equivalent results or effects recited in the claims. That is, it is understood that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but can be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. In general, an amount, size, formulation, parameter or other quantity or characteristic is “about” or “approximate” whether or not expressly stated to be such. It is understood that where “about” is used before a quantitative value, the parameter also includes the specific quantitative value itself, unless specifically stated otherwise. [0043] References in the specification and concluding claims to parts by weight of a particular element or component in a composition denotes the weight relationship between the element or component and any other elements or components in the composition or article for which a part by weight is expressed. Thus, in a compound containing 2 parts by weight of component X and 5 parts by weight component Y, X and Y are present at a weight ratio of 2:5, and are present in such ratio regardless of whether additional components are contained in the compound. [0044] A weight percent (wt. %) of a component, unless specifically stated to the contrary, is based on the total weight of the formulation or composition in which the component is included. [0045] As used herein, “IC₅₀” is intended to refer to the concentration of a substance (e.g., a compound or a drug) that is required for 50% inhibition of a biological process, or component of Attorney Docket No.37759.0543P1 a process, including a protein, subunit, organelle, ribonucleoprotein, etc. In one aspect, an IC50 can refer to the concentration of a substance that is required for 50% inhibition in vivo, as further defined elsewhere herein. In a further aspect, IC₅₀ refers to the half-maximal (50%) inhibitory concentration (IC) of a substance. [0046] As used herein, “EC50” is intended to refer to the concentration of a substance (e.g., a compound or a drug) that is required for 50% agonism of a biological process, or component of a process, including a protein, subunit, organelle, ribonucleoprotein, etc. In one aspect, an EC₅₀ can refer to the concentration of a substance that is required for 50% agonism in vivo, as further defined elsewhere herein. In a further aspect, EC50 refers to the concentration of agonist that provokes a response halfway between the baseline and maximum response. [0047] “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not. [0048] The term “analog” as used herein refers to a chemical compound that is structurally related to boldine. The analog can be prepared from boldine or other suitable starting materials, and thus the term “analog” does not necessarily imply that the compound was derived from or prepared from boldine. [0049] The term “pharmaceutically acceptable salt,” as used herein, refers to an inorganic or organic salt of a disclosed compound that is suitable for administration to a subject. [0050] As used herein, the term “pharmaceutically acceptable carrier” refers to sterile aqueous or nonaqueous solutions, dispersions, suspensions or emulsions, as well as sterile powders for reconstitution into sterile injectable solutions or dispersions just prior to use. Examples of suitable aqueous and nonaqueous carriers, diluents, solvents or vehicles include water, ethanol, polyols (such as glycerol, propylene glycol, polyethylene glycol and the like), carboxymethylcellulose and suitable mixtures thereof, vegetable oils (such as olive oil) and injectable organic esters such as ethyl oleate. Proper fluidity can be maintained, for example, by the use of coating materials such as lecithin, by the maintenance of the required particle size in the case of dispersions and by the use of surfactants. These compositions can also contain adjuvants such as preservatives, wetting agents, emulsifying agents and dispersing agents. Prevention of the action of microorganisms can be ensured by the inclusion of various antibacterial and antifungal agents such as paraben, chlorobutanol, phenol, sorbic acid and the Attorney Docket No.37759.0543P1 like. It can also be desirable to include isotonic agents such as sugars, sodium chloride and the like. Prolonged absorption of the injectable pharmaceutical form can be brought about by the inclusion of agents, such as aluminum monostearate and gelatin, which delay absorption. Injectable depot forms are made by forming microencapsule matrices of the drug in biodegradable polymers such as polylactide-polyglycolide, poly(orthoesters) and poly(anhydrides). Depending upon the ratio of drug to polymer and the nature of the particular polymer employed, the rate of drug release can be controlled. Depot injectable formulations are also prepared by entrapping the drug in liposomes or microemulsions which are compatible with body tissues. The injectable formulations can be sterilized, for example, by filtration through a bacterial-retaining filter or by incorporating sterilizing agents in the form of sterile solid compositions which can be dissolved or dispersed in sterile water or other sterile injectable media just prior to use. Suitable inert carriers can include sugars such as lactose. Desirably, at least 95% by weight of the particles of the active ingredient have an effective particle size in the range of 0.01 to 10 micrometers. [0051] As used herein, the term “by weight,” when used in conjunction with a component, unless specially stated to the contrary is based on the total weight of the formulation or composition in which the component is included. For example, if a particular element or component in a composition or article is said to have 8% by weight, it is understood that this percentage is in relation to a total compositional percentage of 100%. [0052] A weight percent of a component, or weight %, or wt%, unless specifically stated to the contrary, is based on the total weight of the formulation or composition in which the component is included. [0053] As used herein, the term “subject” can be a vertebrate, such as a mammal, a fish, a bird, a reptile, or an amphibian. Thus, the subject can be a human, non-human primate, horse, pig, rabbit, dog, sheep, goat, cow, cat, guinea pig or rodent. The term does not denote a particular age or sex. Thus, adult and newborn subjects, as well as fetuses, whether male or female, are intended to be covered. In one aspect, the subject is a mammal. A patient refers to a subject afflicted with an ailment, disease, or disorder. The term “patient” includes human and veterinary subjects. [0054] As used herein, the terms “treatment” and “treating” refer to the medical management of a subject with the intent to cure, ameliorate, stabilize, or prevent an ailment, disease, Attorney Docket No.37759.0543P1 pathological condition, disorder, or injury. This term includes active treatment, that is, treatment directed specifically toward the improvement of a disease, pathological condition, disorder, or injury, and also includes causal treatment, that is, treatment directed toward removal of the cause of the associated disease, pathological condition, disorder, or injury. In addition, this term includes palliative treatment, that is, treatment designed for the relief of symptoms rather than the curing of the disease, pathological condition, disorder, or injury; preventative treatment, that is, treatment directed to minimizing or partially or completely inhibiting the development of the associated disease, pathological condition, disorder, or injury; and supportive treatment, that is, treatment employed to supplement another specific therapy directed toward the improvement of the associated disease, pathological condition, disorder, or injury. In various aspects, the term covers any treatment of a subject, including a mammal (e.g., a human), and includes: (i) preventing the disorder or condition from occurring in a subject that can be predisposed to the disorder or condition but has not yet been diagnosed as having it; (ii) inhibiting the disorder or condition, i.e., arresting its development or exacerbation thereof; or (iii) relieving the disorder or condition, i.e., promoting healing of the disorder or condition. In one aspect, the subject is a mammal such as a primate, and, in a further aspect, the subject is a human. [0055] As used herein, the term “prevent” or “preventing” refers to precluding, averting, obviating, forestalling, stopping, or hindering something from happening, especially by advance action. It is understood that where reduce, inhibit or prevent are used herein, unless specifically indicated otherwise, the use of the other two words is also expressly disclosed. [0056] As used herein, the term “diagnosed” means having been subjected to a physical examination by a person of skill, for example, a physician, and found to have a condition that can be diagnosed or treated by a disclosed compound. [0057] As used herein, the terms “administering” and “administration” refer to any method of providing a pharmaceutical preparation to a subject. Such methods are well known to those skilled in the art and include, but are not limited to, oral administration, transdermal administration, administration by inhalation, nasal administration, topical administration, intravaginal administration, ophthalmic administration, intraaural administration, intracerebral administration, rectal administration, sublingual administration, buccal administration, and parenteral administration, including injectable such as intravenous administration, intra-arterial administration, intramuscular administration, and subcutaneous administration. Administration Attorney Docket No.37759.0543P1 can be continuous or intermittent. In various aspects, a preparation can be administered therapeutically; that is, administered to treat an existing disease or condition. In further various aspects, a preparation can be administered prophylactically; that is, administered for prevention of a disease or condition. [0058] As used herein, the terms “effective amount” and “amount effective” refer to an amount that is sufficient to achieve the desired result or to have an effect on an undesired condition. For example, a “therapeutically effective amount” refers to an amount that is sufficient to achieve the desired therapeutic result or to have an effect on undesired symptoms, but is generally insufficient to cause adverse side effects. The specific therapeutically effective dose level for any particular patient will depend upon a variety of factors including the disorder being treated and the severity of the disorder; the specific composition employed; the age, body weight, general health, sex and diet of the patient; the time of administration; the route of administration; the rate of excretion of the specific compound employed; the duration of the treatment; drugs used in combination or coincidental with the specific compound employed and like factors well known in the medical arts. For example, it is well within the skill of the art to start doses of a compound at levels lower than those required to achieve the desired therapeutic effect and to gradually increase the dosage until the desired effect is achieved. If desired, the effective daily dose can be divided into multiple doses for purposes of administration. Consequently, single dose compositions can contain such amounts or submultiples thereof to make up the daily dose. The dosage can be adjusted by the individual physician in the event of any contraindications. Dosage can vary, and can be administered in one or more dose administrations daily, for one or several days. Guidance can be found in the literature for appropriate dosages for given classes of pharmaceutical products. In further various aspects, a preparation can be administered in a “prophylactically effective amount”; that is, an amount effective for prevention of a disease or condition. [0059] The “central nervous system” (CNS) includes the brain, spinal cord, optic, olfactory, and auditory systems. The CNS comprises both neurons and glial cells (neuroglia), which are support cells that aid the function of neurons. Oligodendrocytes, astrocytes, and microglia are glial cells within the CNS. Oligodendrocytes myelinate axons in the CNS, while astrocytes contribute to the blood-brain barrier, which separates the CNS from blood proteins and cells, and Attorney Docket No.37759.0543P1 perform a number of supportive functions for neurons. Microglial cells serve immune system functions. [0060] The “peripheral nervous system” (PNS), for purposes of this disclosure, includes the cranial nerves arising from the brain (other than the optic and olfactory nerves), the spinal nerves arising from the spinal cord, sensory nerve cell bodies, and their processes, i.e., all nervous tissue outside of the CNS. The PNS comprises both neurons and glial cells (neuroglia), which are support cells that aid the function of neurons. Glial cells within the PNS are known as Schwann cells, and serve to myelinate axons by providing a sheath that surrounds the axons. In various aspects, the methods and compositions described herein can be applied to different portions of the PNS. [0061] The term “peripheral nerve injury,” as used herein, refers to any injury to a peripheral nerve caused by trauma instead of disease (e.g., a disease such as cancer). “Peripheral nerve injury” encompasses all degrees of nerve injury, including the lowest degree of nerve injury in which the nerve remains intact but signaling ability is damaged, known as neurapraxia. The term also includes the second degree in which the axon is damaged but the surrounding connecting tissue remains intact, known as axonotmesis. Finally, the term encompasses the last degree in which both the axon and connective tissue are damaged, known as neurotmesis. [0062] As used herein, the term “planned nerve injury” refers to any injury to a nerve that is expected or likely to occur as a result of an upcoming surgical procedure such as, for example, a tumor resection. [0063] An “iatrogenic injury,” as used herein, refers to an injury induced unintentionally by a physician or surgeon or by medical treatment or diagnostic procedures. An iatrogenic injury can also be caused by a disease, a harmful complication, or other ill effect due to any medical activity, including diagnosis, intervention, error, or negligence. Exemplary causes of iatrogenic injuries include, but are not limited to, injuries that are the result of a medical treatment, pharmacotherapy, or the application of a medical device. Additional causes of iatrogenic injuries include unintentional mechanical stress during surgery or positioning during anesthesia, injection of neurotoxic substances, compression, tourniquet, dressings, orthotic devices, and radiation. [0064] A “non-iatrogenic injury,” as used herein, refers to an injury that occurs spontaneously without intervention of a physician or surgeon, such as, for example, an injury to a nerve that is not the result of medical treatment or diagnostic procedures. Exemplary causes of Attorney Docket No.37759.0543P1 non-iatrogenic injuries include, but are not limited to, genetics, trauma, and disease (e.g., autoimmune disorders, viral infections). [0065] The terms “recovered expected strength and “expected strength that is recovered,”” as used herein, refer to the percent muscle functionality that is observed following a nerve injury or nerve transection compared to the muscle functionality prior to the injury or transection or compared to a reference muscle functionality. For example, if a left hand is denervated and then undergoes surgical repair, the grip strength of the left hand after injury can be compared to that of the right (uninjured hand), which could be used as a normal reference for that individual. Alternatively, the grip strength of that same hand before and after injury (e.g., a planned injury) can be compared to obtain the recovered expected strength. [0066] The term “sensation neurological exam,” as used herein, refers to standard neurological exams that are used to evaluate sensation such as, for example, sensation of pain (e.g., pin prick), temperature, light touch, position sense, vibration, and discriminative sensations. Exemplary sensation neurological exams include, but are not limited to, two-point discrimination, stereognosis, and graphesthesia. [0067] As used herein, “dosage form” means a pharmacologically active material in a medium, carrier, vehicle, or device suitable for administration to a subject. A dosage forms can comprise inventive a disclosed compound, a product of a disclosed method of making, or a salt, solvate, or polymorph thereof, in combination with a pharmaceutically acceptable excipient, such as a preservative, buffer, saline, or phosphate buffered saline. Dosage forms can be made using conventional pharmaceutical manufacturing and compounding techniques. Dosage forms can comprise inorganic or organic buffers (e.g., sodium or potassium salts of phosphate, carbonate, acetate, or citrate) and pH adjustment agents (e.g., hydrochloric acid, sodium or potassium hydroxide, salts of citrate or acetate, amino acids and their salts) antioxidants (e.g., ascorbic acid, alpha-tocopherol), surfactants (e.g., polysorbate 20, polysorbate 80, polyoxyethylene9-10 nonyl phenol, sodium desoxycholate), solution and/or cryo/lyo stabilizers (e.g., sucrose, lactose, mannitol, trehalose), osmotic adjustment agents (e.g., salts or sugars), antibacterial agents (e.g., benzoic acid, phenol, gentamicin), antifoaming agents (e.g., polydimethylsilozone), preservatives (e.g., thimerosal, 2-phenoxyethanol, EDTA), polymeric stabilizers and viscosity-adjustment agents (e.g., polyvinylpyrrolidone, poloxamer 488, carboxymethylcellulose) and co-solvents (e.g., glycerol, polyethylene glycol, ethanol). A dosage form formulated for injectable use can Attorney Docket No.37759.0543P1 have a disclosed compound, a product of a disclosed method of making, or a salt, solvate, or polymorph thereof, suspended in sterile saline solution for injection together with a preservative. [0068] As used herein, “kit” means a collection of at least two components constituting the kit. Together, the components constitute a functional unit for a given purpose. Individual member components may be physically packaged together or separately. For example, a kit comprising an instruction for using the kit may or may not physically include the instruction with other individual member components. Instead, the instruction can be supplied as a separate member component, either in a paper form or an electronic form which may be supplied on computer readable memory device or downloaded from an internet website, or as a recorded presentation. [0069] As used herein, the terms “therapeutic agent” include any synthetic or naturally occurring biologically active compound or composition of matter which, when administered to an organism (human or nonhuman animal), induces a desired pharmacologic, immunogenic, and/or physiologic effect by local and/or systemic action. The term therefore encompasses those compounds or chemicals traditionally regarded as drugs, vaccines, and biopharmaceuticals including molecules such as proteins, peptides, hormones, nucleic acids, gene constructs and the like. Examples of therapeutic agents are described in well-known literature references such as the Merck Index (14^th edition), the Physicians' Desk Reference (64^th edition), and The Pharmacological Basis of Therapeutics (12^th edition) , and they include, without limitation, medicaments; vitamins; mineral supplements; substances used for the treatment, prevention, diagnosis, cure or mitigation of a disease or illness; substances that affect the structure or function of the body, or pro-drugs, which become biologically active or more active after they have been placed in a physiological environment. For example, the term “therapeutic agent” includes compounds or compositions for use in all of the major therapeutic areas including, but not limited to, adjuvants; anti-infectives such as antibiotics and antiviral agents; anti-cancer and anti-neoplastic agents such as kinase inhibitors, poly ADP ribose polymerase (PARP) inhibitors and other DNA damage response modifiers, epigenetic agents such as bromodomain and extra- terminal (BET) inhibitors, histone deacetylase (HDAc) inhibitors, iron chelotors and other ribonucleotides reductase inhibitors, proteasome inhibitors and Nedd8-activating enzyme (NAE) inhibitors, mammalian target of rapamycin (mTOR) inhibitors, traditional cytotoxic agents such as paclitaxel, dox, irinotecan, and platinum compounds, immune checkpoint blockade agents Attorney Docket No.37759.0543P1 such as cytotoxic T lymphocyte antigen-4 (CTLA-4) monoclonal antibody (mAB), programmed cell death protein 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) mAB, cluster of differentiation 47 (CD47) mAB, toll-like receptor (TLR) agonists and other immune modifiers, cell therapeutics such as chimeric antigen receptor T-cell (CAR-T)/chimeric antigen receptor natural killer (CAR-NK) cells, and proteins such as interferons (IFNs), interleukins (ILs), and mAbs; anti-ALS agents such as entry inhibitors, fusion inhibitors, non-nucleoside reverse transcriptase inhibitors (NNRTIs), nucleoside reverse transcriptase inhibitors (NRTIs), nucleotide reverse transcriptase inhibitors, NCP7 inhibitors, protease inhibitors, and integrase inhibitors; analgesics and analgesic combinations, anorexics, anti-inflammatory agents, anti- epileptics, local and general anesthetics, hypnotics, sedatives, antipsychotic agents, neuroleptic agents, antidepressants, anxiolytics, antagonists, neuron blocking agents, anticholinergic and cholinomimetic agents, antimuscarinic and muscarinic agents, antiadrenergics, antiarrhythmics, antihypertensive agents, hormones, and nutrients, antiarthritics, antiasthmatic agents, anticonvulsants, antihistamines, antinauseants, antineoplastics, antipruritics, antipyretics; antispasmodics, cardiovascular preparations (including calcium channel blockers, beta-blockers, beta-agonists and antiarrythmics), antihypertensives, diuretics, vasodilators; central nervous system stimulants; cough and cold preparations; decongestants; diagnostics; hormones; bone growth stimulants and bone resorption inhibitors; immunosuppressives; muscle relaxants; psychostimulants; sedatives; tranquilizers; proteins, peptides, and fragments thereof (whether naturally occurring, chemically synthesized or recombinantly produced); and nucleic acid molecules (polymeric forms of two or more nucleotides, either ribonucleotides (RNA) or deoxyribonucleotides (DNA) including both double- and single-stranded molecules, gene constructs, expression vectors, antisense molecules and the like), small molecules (e.g., doxorubicin) and other biologically active macromolecules such as, for example, proteins and enzymes. The agent may be a biologically active agent used in medical, including veterinary, applications and in agriculture, such as with plants, as well as other areas. The term "therapeutic agent" also includes without limitation, medicaments; vitamins; mineral supplements; substances used for the treatment, prevention, diagnosis, cure or mitigation of disease or illness; or substances which affect the structure or function of the body; or pro- drugs, which become biologically active or more active after they have been placed in a predetermined physiological environment. Attorney Docket No.37759.0543P1 [0070] As used herein, the term “substantially,” in, for example, the context “substantially free of” refers to a composition having less than about 10% by weight, e.g., less than about 5%, less than about 1%, less than about 0.5%, less than about 0.1%, less than about 0.05%, or less than about 0.01% by weight of the stated material, based on the total weight of the composition. [0071] It is further understood that the term “substantially,” when used in reference to a composition, refers to at least about 60% by weight, e.g., at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 99%, or about 100% by weight, based on the total weight of the composition, of a specified feature, component, or a combination of the components. It is further understood that if the composition comprises more than one component, the two or more components can be present in any ratio predetermined by one of ordinary skill in the art. [0072] As used herein, the term “derivative” refers to a compound having a structure similar to the structure of a certain compound (e.g., a compound disclosed herein) and whose structure is sufficiently similar to those disclosed herein and based upon that similarity, would be expected by one skilled in the art to exhibit the same or similar activities and utilities as the claimed compounds, or to induce, as a precursor, the same or similar activities and utilities as the claimed compounds. Exemplary derivatives include salts, esters, and amides, salts of esters or amides, and N-oxides of a parent compound. [0073] As used herein, the term “substituted” is contemplated to include all permissible substituents of organic compounds. In a broad aspect, the permissible substituents include acyclic and cyclic, branched and unbranched, carbocyclic and heterocyclic, and aromatic and nonaromatic substituents of organic compounds. Illustrative substituents include, for example, those described below. The permissible substituents can be one or more and the same or different for appropriate organic compounds. For purposes of this disclosure, the heteroatoms, such as nitrogen, can have hydrogen substituents and/or any permissible substituents of organic compounds described herein which satisfy the valences of the heteroatoms. This disclosure is not intended to be limited in any manner by the permissible substituents of organic compounds. Also, the terms “substitution” or “substituted with” include the implicit proviso that such substitution is in accordance with permitted valence of the substituted atom and the substituent, Attorney Docket No.37759.0543P1 and that the substitution results in a stable compound, e.g., a compound that does not spontaneously undergo transformation such as by rearrangement, cyclization, elimination, etc. It is also contemplated that, in certain aspects, unless expressly indicated to the contrary, individual substituents can be further optionally substituted (i.e., further substituted or unsubstituted). [0074] The term “aliphatic” or “aliphatic group,” as used herein, denotes a hydrocarbon moiety that may be straight chain (i.e., unbranched), branched, or cyclic (including fused, bridging, and spirofused polycyclic) and may be completely saturated or may contain one or more units of unsaturation, but which is not aromatic. Unless otherwise specified, aliphatic groups contain 1-20 carbon atoms. Aliphatic groups include, but are not limited to, linear or branched, alkyl, alkenyl, and alkynyl groups, and hybrids thereof such as (cycloalkyl)alkyl, (cycloalkenyl)alkyl or (cycloalkyl)alkenyl. [0075] The term “alkyl” as used herein is a branched or unbranched saturated hydrocarbon group of 1 to 24 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s- butyl, t-butyl, n-pentyl, isopentyl, s-pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, eicosyl, tetracosyl, and the like. The alkyl group can be cyclic or acyclic. The alkyl group can be branched or unbranched. The alkyl group can also be substituted or unsubstituted. For example, the alkyl group can be substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, amino, ether, halide, hydroxy, nitro, silyl, sulfo-oxo, or thiol, as described herein. A “lower alkyl” group is an alkyl group containing from one to six (e.g., from one to four) carbon atoms. The term alkyl group can also be a C1 alkyl, C1- C2 alkyl, C1-C3 alkyl, C1-C4 alkyl, C1-C5 alkyl, C1-C6 alkyl, C1-C7 alkyl, C1-C8 alkyl, C1- C9 alkyl, C1-C10 alkyl, and the like up to and including a C1-C24 alkyl. [0076] Throughout the specification “alkyl” is generally used to refer to both unsubstituted alkyl groups and substituted alkyl groups; however, substituted alkyl groups are also specifically referred to herein by identifying the specific substituent(s) on the alkyl group. For example, the term “halogenated alkyl” or “haloalkyl” specifically refers to an alkyl group that is substituted with one or more halide, e.g., fluorine, chlorine, bromine, or iodine. Alternatively, the term “monohaloalkyl” specifically refers to an alkyl group that is substituted with a single halide, e.g. fluorine, chlorine, bromine, or iodine. The term “polyhaloalkyl” specifically refers to an alkyl group that is independently substituted with two or more halides, i.e. each halide substituent need not be the same halide as another halide substituent, nor do the multiple instances of a halide Attorney Docket No.37759.0543P1 substituent need to be on the same carbon. The term “alkoxyalkyl” specifically refers to an alkyl group that is substituted with one or more alkoxy groups, as described below. The term “aminoalkyl” specifically refers to an alkyl group that is substituted with one or more amino groups. The term “hydroxyalkyl” specifically refers to an alkyl group that is substituted with one or more hydroxy groups. When “alkyl” is used in one instance and a specific term such as “hydroxyalkyl” is used in another, it is not meant to imply that the term “alkyl” does not also refer to specific terms such as “hydroxyalkyl” and the like. [0077] This practice is also used for other groups described. That is, while a term such as “cycloalkyl” refers to both unsubstituted and substituted cycloalkyl moieties, the substituted moieties can, in addition, be specifically identified herein; for example, a particular substituted cycloalkyl can be referred to as, e.g., an “alkylcycloalkyl.” Similarly, a substituted alkoxy can be specifically referred to as, e.g., a “halogenated alkoxy,” a particular substituted alkenyl can be, e.g., an “alkenylalcohol,” and the like. Again, the practice of using a general term, such as “cycloalkyl,” and a specific term, such as “alkylcycloalkyl,” is not meant to imply that the general term does not also include the specific term. [0078] The term “cycloalkyl” as used herein is a non-aromatic carbon-based ring composed of at least three carbon atoms. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, norbornyl, and the like. The term “heterocycloalkyl” is a non-aromatic carbon-based ring type of cycloalkyl group as defined above, and is included within the meaning of the term “cycloalkyl,” where at least one of the carbon atoms of the ring is replaced with a heteroatom such as, but not limited to, nitrogen, oxygen, sulfur, or phosphorus. The cycloalkyl group and heterocycloalkyl group can be substituted or unsubstituted. The cycloalkyl group and heterocycloalkyl group can be substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, amino, ether, halide, hydroxy, nitro, silyl, sulfo-oxo, or thiol as described herein. [0079] The term “polyalkylene group” as used herein is a group having two or more CH₂ groups linked to one another. The polyalkylene group can be represented by the formula — (CH2)a—, where “a” is an integer of from 2 to 500. [0080] The terms “alkoxy” and “alkoxyl” as used herein to refer to an alkyl or cycloalkyl group bonded through an ether linkage; that is, an “alkoxy” group can be defined as —OA¹ where A¹ is alkyl or cycloalkyl as defined above. “Alkoxy” also includes polymers of alkoxy Attorney Docket No.37759.0543P1 groups as just described; that is, an alkoxy can be a polyether such as —OA¹—OA² or —OA¹— (OA²)a—OA³, where “a” is an integer of from 1 to 200 and A¹, A², and A³ are alkyl and/or cycloalkyl groups. [0081] The term “alkenyl” as used herein is a hydrocarbon group of from 2 to 24 carbon atoms with a structural formula containing at least one carbon-carbon double bond. Asymmetric structures such as (A¹A²)C=C(A³A⁴) are intended to include both the E and Z isomers. This can be presumed in structural formulae herein wherein an asymmetric alkene is present, or it can be explicitly indicated by the bond symbol C=C. The alkenyl group can be substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiol, as described herein. [0082] The term “cycloalkenyl” as used herein is a non-aromatic carbon-based ring composed of at least three carbon atoms and containing at least one carbon-carbon double bound, i.e., C=C. Examples of cycloalkenyl groups include, but are not limited to, cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclopentadienyl, cyclohexenyl, cyclohexadienyl, norbornenyl, and the like. The term “heterocycloalkenyl” is a type of cycloalkenyl group as defined above, and is included within the meaning of the term “cycloalkenyl,” where at least one of the carbon atoms of the ring is replaced with a heteroatom such as, but not limited to, nitrogen, oxygen, sulfur, or phosphorus. The cycloalkenyl group and heterocycloalkenyl group can be substituted or unsubstituted. The cycloalkenyl group and heterocycloalkenyl group can be substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiol as described herein. [0083] The term “alkynyl” as used herein is a hydrocarbon group of 2 to 24 carbon atoms with a structural formula containing at least one carbon-carbon triple bond. The alkynyl group can be unsubstituted or substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiol, as described herein. [0084] The term “cycloalkynyl” as used herein is a non-aromatic carbon-based ring composed of at least seven carbon atoms and containing at least one carbon-carbon triple bound. Attorney Docket No.37759.0543P1 Examples of cycloalkynyl groups include, but are not limited to, cycloheptynyl, cyclooctynyl, cyclononynyl, and the like. The term “heterocycloalkynyl” is a type of cycloalkenyl group as defined above, and is included within the meaning of the term “cycloalkynyl,” where at least one of the carbon atoms of the ring is replaced with a heteroatom such as, but not limited to, nitrogen, oxygen, sulfur, or phosphorus. The cycloalkynyl group and heterocycloalkynyl group can be substituted or unsubstituted. The cycloalkynyl group and heterocycloalkynyl group can be substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiol as described herein. [0085] The term “aromatic group” as used herein refers to a ring structure having cyclic clouds of delocalized π electrons above and below the plane of the molecule, where the π clouds contain (4n+2) π electrons. A further discussion of aromaticity is found in Morrison and Boyd, Organic Chemistry, (5th Ed., 1987), Chapter 13, entitled “Aromaticity,” pages 477-497, incorporated herein by reference. The term “aromatic group” is inclusive of both aryl and heteroaryl groups. [0086] The term “aryl” as used herein is a group that contains any carbon-based aromatic group including, but not limited to, benzene, naphthalene, phenyl, biphenyl, anthracene, and the like. The aryl group can be substituted or unsubstituted. The aryl group can be substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, ─NH₂, carboxylic acid, ester, ether, halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiol as described herein. The term “biaryl” is a specific type of aryl group and is included in the definition of “aryl.” In addition, the aryl group can be a single ring structure or comprise multiple ring structures that are either fused ring structures or attached via one or more bridging groups such as a carbon-carbon bond. For example, biaryl can be two aryl groups that are bound together via a fused ring structure, as in naphthalene, or are attached via one or more carbon-carbon bonds, as in biphenyl. [0087] The term “aldehyde” as used herein is represented by the formula —C(O)H. Throughout this specification “C(O)” is a short hand notation for a carbonyl group, i.e., C=O. [0088] The terms “amine” or “amino” as used herein are represented by the formula — NA¹A², where A¹ and A² can be, independently, hydrogen or alkyl, cycloalkyl, alkenyl, Attorney Docket No.37759.0543P1 cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein. A specific example of amino is ─NH2. [0089] The term “alkylamino” as used herein is represented by the formula —NH(-alkyl) where alkyl is a described herein. Representative examples include, but are not limited to, methylamino group, ethylamino group, propylamino group, isopropylamino group, butylamino group, isobutylamino group, (sec-butyl)amino group, (tert-butyl)amino group, pentylamino group, isopentylamino group, (tert-pentyl)amino group, hexylamino group, and the like. [0090] The term “dialkylamino” as used herein is represented by the formula —N(-alkyl)2 where alkyl is a described herein. Representative examples include, but are not limited to, dimethylamino group, diethylamino group, dipropylamino group, diisopropylamino group, dibutylamino group, diisobutylamino group, di(sec-butyl)amino group, di(tert-butyl)amino group, dipentylamino group, diisopentylamino group, di(tert-pentyl)amino group, dihexylamino group, N-ethyl-N-methylamino group, N-methyl-N-propylamino group, N-ethyl-N-propylamino group and the like. [0091] The term “carboxylic acid” as used herein is represented by the formula —C(O)OH. [0092] The term “ester” as used herein is represented by the formula —OC(O)A¹ or — C(O)OA¹, where A¹ can be alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein. The term “polyester” as used herein is represented by the formula —(A¹O(O)C-A²-C(O)O)a— or —(A¹O(O)C-A²-OC(O))a—, where A¹ and A² can be, independently, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group described herein and “a” is an integer from 1 to 500. “Polyester” is as the term used to describe a group that is produced by the reaction between a compound having at least two carboxylic acid groups with a compound having at least two hydroxyl groups. [0093] The term “ether” as used herein is represented by the formula A¹OA², where A¹ and A² can be, independently, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group described herein. The term “polyether” as used herein is represented by the formula —(A¹O-A²O)_a—, where A¹ and A² can be, independently, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group described herein and “a” is an integer of from 1 to 500. Examples of polyether groups include polyethylene oxide, polypropylene oxide, and polybutylene oxide. Attorney Docket No.37759.0543P1 [0094] The terms “halo,” “halogen,” or “halide,” as used herein can be used interchangeably and refer to F, Cl, Br, or I. [0095] The terms “pseudohalide,” “pseudohalogen,” or “pseudohalo,” as used herein can be used interchangeably and refer to functional groups that behave substantially similar to halides. Such functional groups include, by way of example, cyano, thiocyanato, azido, trifluoromethyl, trifluoromethoxy, perfluoroalkyl, and perfluoroalkoxy groups. [0096] The term “heteroalkyl,” as used herein refers to an alkyl group containing at least one heteroatom. Suitable heteroatoms include, but are not limited to, O, N, Si, P and S, wherein the nitrogen, phosphorous and sulfur atoms are optionally oxidized, and the nitrogen heteroatom is optionally quaternized. Heteroalkyls can be substituted as defined above for alkyl groups. [0097] The term “heteroaryl,” as used herein, refers to an aromatic group that has at least one heteroatom incorporated within the ring of the aromatic group. Examples of heteroatoms include, but are not limited to, nitrogen, oxygen, sulfur, and phosphorus, where N-oxides, sulfur oxides, and dioxides are permissible heteroatom substitutions. The heteroaryl group can be substituted or unsubstituted. The heteroaryl group can be substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, amino, ether, halide, hydroxy, nitro, silyl, sulfo-oxo, or thiol as described herein. Heteroaryl groups can be monocyclic, or alternatively fused ring systems. Heteroaryl groups include, but are not limited to, furyl, imidazolyl, pyrimidinyl, tetrazolyl, thienyl, pyridinyl, pyrrolyl, N-methylpyrrolyl, quinolinyl, isoquinolinyl, pyrazolyl, triazolyl, thiazolyl, oxazolyl, isoxazolyl, oxadiazolyl, thiadiazolyl, isothiazolyl, pyridazinyl, pyrazinyl, benzofuranyl, benzodioxolyl, benzothiophenyl, indolyl, indazolyl, benzimidazolyl, imidazopyridinyl, pyrazolopyridinyl, and pyrazolopyrimidinyl. Further not limiting examples of heteroaryl groups include, but are not limited to, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, thiophenyl, pyrazolyl, imidazolyl, benzo[d]oxazolyl, benzo[d]thiazolyl, quinolinyl, quinazolinyl, indazolyl, imidazo[1,2-b]pyridazinyl, imidazo[1,2-a]pyrazinyl, benzo[c][1,2,5]thiadiazolyl, benzo[c][1,2,5]oxadiazolyl, and pyrido[2,3-b]pyrazinyl. [0098] The terms “heterocycle” or “heterocyclyl,” as used herein can be used interchangeably and refer to single and multi-cyclic aromatic or non-aromatic ring systems in which at least one of the ring members is other than carbon. Thus, the term is inclusive of, but not limited to, “heterocycloalkyl,” “heteroaryl,” “bicyclic heterocycle,” and “polycyclic heterocycle.” Heterocycle includes pyridine, pyrimidine, furan, thiophene, pyrrole, isoxazole, Attorney Docket No.37759.0543P1 isothiazole, pyrazole, oxazole, thiazole, imidazole, oxazole, including, 1,2,3-oxadiazole, 1,2,5- oxadiazole and 1,3,4-oxadiazole, thiadiazole, including, 1,2,3-thiadiazole, 1,2,5-thiadiazole, and 1,3,4-thiadiazole, triazole, including, 1,2,3-triazole, 1,3,4-triazole, tetrazole, including 1,2,3,4- tetrazole and 1,2,4,5-tetrazole, pyridazine, pyrazine, triazine, including 1,2,4-triazine and 1,3,5- triazine, tetrazine, including 1,2,4,5-tetrazine, pyrrolidine, piperidine, piperazine, morpholine, azetidine, tetrahydropyran, tetrahydrofuran, dioxane, and the like. The term heterocyclyl group can also be a C2 heterocyclyl, C2-C3 heterocyclyl, C2-C4 heterocyclyl, C2-C5 heterocyclyl, C2- C6 heterocyclyl, C2-C7 heterocyclyl, C2-C8 heterocyclyl, C2-C9 heterocyclyl, C2-C10 heterocyclyl, C2-C11 heterocyclyl, and the like up to and including a C2-C18 heterocyclyl. For example, a C2 heterocyclyl comprises a group which has two carbon atoms and at least one heteroatom, including, but not limited to, aziridinyl, diazetidinyl, dihydrodiazetyl, oxiranyl, thiiranyl, and the like. Alternatively, for example, a C5 heterocyclyl comprises a group that has five carbon atoms and at least one heteroatom, including, but not limited to, piperidinyl, tetrahydropyranyl, tetrahydrothiopyranyl, diazepanyl, pyridinyl, and the like. It is understood that a heterocyclyl group may be bound either through a heteroatom in the ring, where chemically possible, or one of carbons comprising the heterocyclyl ring. [0099] The term “bicyclic heterocycle” or “bicyclic heterocyclyl,” as used herein refers to a ring system in which at least one of the ring members is other than carbon. Bicyclic heterocyclyl encompasses ring systems wherein an aromatic ring is fused with another aromatic ring, or wherein an aromatic ring is fused with a non-aromatic ring. Bicyclic heterocyclyl encompasses ring systems wherein a benzene ring is fused to a 5- or a 6-membered ring containing 1, 2 or 3 ring heteroatoms or wherein a pyridine ring is fused to a 5- or a 6-membered ring containing 1, 2 or 3 ring heteroatoms. Bicyclic heterocyclic groups include, but are not limited to, indolyl, indazolyl, pyrazolo[1,5-a]pyridinyl, benzofuranyl, quinolinyl, quinoxalinyl, 1,3-benzodioxolyl, 2,3-dihydro-1,4-benzodioxinyl, 3,4-dihydro-2H-chromenyl, 1H-pyrazolo[4,3-c]pyridin-3-yl; 1H- pyrrolo[3,2-b]pyridin-3-yl; and 1H-pyrazolo[3,2-b]pyridin-3-yl. [00100] The term “heterocycloalkyl” as used herein refers to an aliphatic, partially unsaturated or fully saturated, 3- to 14-membered ring system, including single rings of 3 to 8 atoms and bi- and tricyclic ring systems. The heterocycloalkyl ring-systems include one to four heteroatoms independently selected from oxygen, nitrogen, and sulfur, wherein a nitrogen and sulfur heteroatom optionally can be oxidized and a nitrogen heteroatom optionally can be substituted. Attorney Docket No.37759.0543P1 Representative heterocycloalkyl groups include, but are not limited to, pyrrolidinyl, pyrazolinyl, pyrazolidinyl, imidazolinyl, imidazolidinyl, piperidinyl, piperazinyl, oxazolidinyl, isoxazolidinyl, morpholinyl, thiazolidinyl, isothiazolidinyl, and tetrahydrofuryl. [00101] The term “hydroxyl” or “hydroxyl” as used herein is represented by the formula — OH. [00102] The term “ketone” as used herein is represented by the formula A¹C(O)A², where A¹ and A² can be, independently, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein. [00103] The term “azide” or “azido” as used herein is represented by the formula —N3. [00104] The term “nitro” as used herein is represented by the formula —NO₂. [00105] The term “nitrile” or “cyano” as used herein is represented by the formula —CN. [00106] The term “silyl” as used herein is represented by the formula —SiA¹A²A³, where A¹, A², and A³ can be, independently, hydrogen or an alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein. [00107] The term “sulfo-oxo” as used herein is represented by the formulas —S(O)A¹, — S(O)₂A¹, —OS(O)₂A¹, or —OS(O)₂OA¹, where A¹ can be hydrogen or an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein. Throughout this specification “S(O)” is a short hand notation for S=O. The term “sulfonyl” is used herein to refer to the sulfo-oxo group represented by the formula —S(O)2A¹, where A¹ can be hydrogen or an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein. The term “sulfone” as used herein is represented by the formula A¹S(O)2A², where A¹ and A² can be, independently, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein. The term “sulfoxide” as used herein is represented by the formula A¹S(O)A², where A¹ and A² can be, independently, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein. [00108] The term “thiol” as used herein is represented by the formula —SH. [00109] “R¹,” “R²,” “R³,” and “Rⁿ,” where n is an integer, as used herein can, independently, possess one or more of the groups listed above. For example, if R¹ is a straight chain alkyl group, one of the hydrogen atoms of the alkyl group can optionally be substituted with a hydroxyl group, an alkoxy group, an alkyl group, a halide, and the like. Depending upon the groups that Attorney Docket No.37759.0543P1 are selected, a first group can be incorporated within second group or, alternatively, the first group can be pendant (i.e., attached) to the second group. For example, with the phrase “an alkyl group comprising an amino group,” the amino group can be incorporated within the backbone of the alkyl group. Alternatively, the amino group can be attached to the backbone of the alkyl group. The nature of the group(s) that is (are) selected will determine if the first group is embedded or attached to the second group. [00110] As described herein, compounds of the invention may contain “optionally substituted” moieties. In general, the term “substituted,” whether preceded by the term “optionally” or not, means that one or more hydrogen of the designated moiety are replaced with a suitable substituent. Unless otherwise indicated, an “optionally substituted” group may have a suitable substituent at each substitutable position of the group, and when more than one position in any given structure may be substituted with more than one substituent selected from a specified group, the substituent may be either the same or different at every position. Combinations of substituents envisioned by this invention are preferably those that result in the formation of stable or chemically feasible compounds. In is also contemplated that, in certain aspects, unless expressly indicated to the contrary, individual substituents can be further optionally substituted (i.e., further substituted or unsubstituted). [00111] The term “stable,” as used herein, refers to compounds that are not substantially altered when subjected to conditions to allow for their production, detection, and, in certain aspects, their recovery, purification, and use for one or more of the purposes disclosed herein. [00112] Suitable monovalent substituents on a substitutable carbon atom of an “optionally substituted” group are independently halogen; –(CH2)0–4R ^; –(CH2)0–4OR ^; -O(CH2)0-4R^o, –O– (CH2)0–4C(O)OR°; –(CH2)0–4CH(OR ^)2; –(CH2)0–4SR ^; –(CH2)0–4Ph, which may be substituted with R°; –(CH2)0–4O(CH2)0–1Ph which may be substituted with R°; –CH=CHPh, which may be substituted with R°; –(CH₂)_0–4O(CH₂)_0–1-pyridyl which may be substituted with R°; –NO₂; –CN; –N₃; -(CH₂)_0–4N(R ^)₂; –(CH₂)_0–4N(R ^)C(O)R ^; –N(R ^)C(S)R ^; –(CH₂)_{0– 4}N(R ^)C(O)NR ^₂; -N(R ^)C(S)NR ^₂; –(CH₂)_0–4N(R ^)C(O)OR ^; – N(R ^)N(R ^)C(O)R ^; -N(R ^)N(R ^)C(O)NR ^₂; -N(R ^)N(R ^)C(O)OR ^; –(CH₂)_0–4C(O)R ^; – C(S)R ^; –(CH₂)_0–4C(O)OR ^; –(CH₂)_0–4C(O)SR ^; -(CH₂)_0–4C(O)OSiR ^₃; –(CH₂)_0–4OC(O)R ^; – OC(O)(CH₂)_0–4SR–, SC(S)SR°; –(CH₂)_0–4SC(O)R ^; –(CH₂)_0–4C(O)NR ^₂; –C(S)NR ^₂; – C(S)SR°; -(CH₂)_0–4OC(O)NR ^₂; -C(O)N(OR ^)R ^; –C(O)C(O)R ^; –C(O)CH₂C(O)R ^; – Attorney Docket No.37759.0543P1 C(NOR ^)R ^; -(CH2)0–4SSR ^; –(CH2)0–4S(O)2R ^; –(CH2)0–4S(O)2OR ^; –(CH2)0–4OS(O)2R ^; – S(O)2NR ^2; -(CH2)0–4S(O)R ^; -N(R ^)S(O)2NR ^2; –N(R ^)S(O)2R ^; –N(OR ^)R ^; –C(NH)NR ^2; – P(O)₂R ^; -P(O)R ^₂; -OP(O)R ^₂; –OP(O)(OR ^)₂; SiR ^₃; –(C_1–4 straight or branched alkylene)O– N(R ^)2; or –(C1–4 straight or branched alkylene)C(O)O–N(R ^)2, wherein each R ^ may be substituted as defined below and is independently hydrogen, C_1–6 aliphatic, –CH₂Ph, –O(CH₂)_0– 1Ph, -CH2-(5-6 membered heteroaryl ring), or a 5–6–membered saturated, partially unsaturated, or aryl ring having 0–4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or, notwithstanding the definition above, two independent occurrences of R ^, taken together with their intervening atom(s), form a 3–12–membered saturated, partially unsaturated, or aryl mono– or bicyclic ring having 0–4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, which may be substituted as defined below. [00113] Suitable monovalent substituents on R ^ (or the ring formed by taking two independent occurrences of R ^ together with their intervening atoms), are independently halogen, –(CH₂)_0–2R ^{^}, –(haloR ^{^}), –(CH₂)_0–2OH, –(CH₂)_0–2OR ^{^}, –(CH₂)_{0– 2}CH(OR ^{^})₂; -O(haloR ^{^}), –CN, –N₃, –(CH₂)_0–2C(O)R ^{^}, –(CH₂)_0–2C(O)OH, –(CH₂)_0–2C(O)OR ^{^}, – (CH2)0–2SR ^{^}, –(CH2)0–2SH, –(CH2)0–2NH2, –(CH2)0–2NHR ^{^}, –(CH2)0–2NR ^{^}2, –NO2, –SiR ^{^}3, – OSiR ^{^}3, -C(O)SR ^{^}, –(C1–4 straight or branched alkylene)C(O)OR ^{^}, or –SSR ^{^} wherein each R ^{^} is unsubstituted or where preceded by “halo” is substituted only with one or more halogens, and is independently selected from C1–4 aliphatic, –CH2Ph, –O(CH2)0–1Ph, or a 5–6–membered saturated, partially unsaturated, or aryl ring having 0–4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. Suitable divalent substituents on a saturated carbon atom of R ^ include =O and =S. [00114] Suitable divalent substituents on a saturated carbon atom of an “optionally substituted” group include the following: =O, =S, =NNR^*2, =NNHC(O)R^*, =NNHC(O)OR^*, =NNHS(O)2R^*, =NR^*, =NOR^*, –O(C(R^*2))2–3O–, or –S(C(R^*2))2–3S–, wherein each independent

aliphatic which may be substituted as defined below, or an unsubstituted 5–6–membered saturated, partially unsaturated, or aryl ring having 0– 4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. Suitable divalent substituents that are bound to vicinal substitutable carbons of an “optionally substituted” group include: –O(CR^*2)2–3O–, wherein each independent occurrence of R^* is selected from hydrogen, C1–6 aliphatic which may be substituted as defined below, or an unsubstituted 5–6–membered Attorney Docket No.37759.0543P1 saturated, partially unsaturated, or aryl ring having 0–4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. [00115] Suitable substituents on the aliphatic group of R^* include halogen, – R ^{^}, -(haloR ^{^}), -OH, –OR ^{^}, –O(haloR ^{^}), –CN, –C(O)OH, –C(O)OR ^{^}, –NH2, –NHR ^{^}, –NR ^{^}2, or –NO2, wherein each R ^{^} is unsubstituted or where preceded by “halo” is substituted only with one or more halogens, and is independently C_1–4 aliphatic, –CH₂Ph, –O(CH₂)_0–1Ph, or a 5–6– membered saturated, partially unsaturated, or aryl ring having 0–4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. [00116] Suitable substituents on a substitutable nitrogen of an “optionally substituted” group include –R^†, –NR^† ₂, –C(O)R^†, –C(O)OR^†, –C(O)C(O)R^†, –C(O)CH₂C(O)R^†, – S(O)2R^†, -S(O)2NR^†2, –C(S)NR^†2, –C(NH)NR^†2, or –N(R^†)S(O)2R^†; wherein each R^† is independently hydrogen, C1–6 aliphatic which may be substituted as defined below, unsubstituted –OPh, or an unsubstituted 5–6–membered saturated, partially unsaturated, or aryl ring having 0– 4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or, notwithstanding the definition above, two independent occurrences of R^†, taken together with their intervening atom(s) form an unsubstituted 3–12–membered saturated, partially unsaturated, or aryl mono– or bicyclic ring having 0–4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. [00117] Suitable substituents on the aliphatic group of R^† are independently halogen, – R ^{^}, -(haloR ^{^}), –OH, –OR ^{^}, –O(haloR ^{^}), –CN, –C(O)OH, –C(O)OR ^{^}, –NH2, –NHR ^{^}, –NR ^{^}2, or –NO₂, wherein each R ^{^} is unsubstituted or where preceded by “halo” is substituted only with one or more halogens, and is independently C1–4 aliphatic, –CH2Ph, –O(CH2)0–1Ph, or a 5–6– membered saturated, partially unsaturated, or aryl ring having 0–4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. [00118] The term “leaving group” refers to an atom (or a group of atoms) with electron withdrawing ability that can be displaced as a stable species, taking with it the bonding electrons. Examples of suitable leaving groups include halides and sulfonate esters, including, but not limited to, triflate, mesylate, tosylate, and brosylate. [00119] The terms “hydrolysable group” and “hydrolysable moiety” refer to a functional group capable of undergoing hydrolysis, e.g., under basic or acidic conditions. Examples of hydrolysable residues include, without limitation, acid halides, activated carboxylic acids, and Attorney Docket No.37759.0543P1 various protecting groups known in the art (see, for example, “Protective Groups in Organic Synthesis,” T. W. Greene, P. G. M. Wuts, Wiley-Interscience, 1999). [00120] The term “organic residue” defines a carbon-containing residue, i.e., a residue comprising at least one carbon atom, and includes but is not limited to the carbon-containing groups, residues, or radicals defined hereinabove. Organic residues can contain various heteroatoms, or be bonded to another molecule through a heteroatom, including oxygen, nitrogen, sulfur, phosphorus, or the like. Examples of organic residues include but are not limited alkyl or substituted alkyls, alkoxy or substituted alkoxy, mono or di-substituted amino, amide groups, etc. Organic residues can preferably comprise 1 to 18 carbon atoms, 1 to 15, carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. In a further aspect, an organic residue can comprise 2 to 18 carbon atoms, 2 to 15, carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, 2 to 4 carbon atoms, or 2 to 4 carbon atoms. [00121] A very close synonym of the term “residue” is the term “radical,” which as used in the specification and concluding claims, refers to a fragment, group, or substructure of a molecule described herein, regardless of how the molecule is prepared. For example, a 2,4- thiazolidinedione radical in a particular compound has the structure: , regardless of whether thiazolidinedione

the compound. In some embodiments the radical (for example an alkyl) can be further modified (i.e., substituted alkyl) by having bonded thereto one or more “substituent radicals.” The number of atoms in a given radical is not critical to the present invention unless it is indicated to the contrary elsewhere herein. [00122] “Organic radicals,” as the term is defined and used herein, contain one or more carbon atoms. An organic radical can have, for example, 1-26 carbon atoms, 1-18 carbon atoms, 1-12 carbon atoms, 1-8 carbon atoms, 1-6 carbon atoms, or 1-4 carbon atoms. In a further aspect, an organic radical can have 2-26 carbon atoms, 2-18 carbon atoms, 2-12 carbon atoms, 2-8 carbon atoms, 2-6 carbon atoms, or 2-4 carbon atoms. Organic radicals often have hydrogen bound to at least some of the carbon atoms of the organic radical. One example, of an organic radical that comprises no inorganic atoms is a 5, 6, 7, 8-tetrahydro-2-naphthyl radical. In some embodiments, an organic radical can contain 1-10 inorganic heteroatoms bound thereto or Attorney Docket No.37759.0543P1 therein, including halogens, oxygen, sulfur, nitrogen, phosphorus, and the like. Examples of organic radicals include but are not limited to an alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, mono-substituted amino, di-substituted amino, acyloxy, cyano, carboxy, carboalkoxy, alkylcarboxamide, substituted alkylcarboxamide, dialkylcarboxamide, substituted dialkylcarboxamide, alkylsulfonyl, alkylsulfinyl, thioalkyl, thiohaloalkyl, alkoxy, substituted alkoxy, haloalkyl, haloalkoxy, aryl, substituted aryl, heteroaryl, heterocyclic, or substituted heterocyclic radicals, wherein the terms are defined elsewhere herein. A few non-limiting examples of organic radicals that include heteroatoms include alkoxy radicals, trifluoromethoxy radicals, acetoxy radicals, dimethylamino radicals and the like. [00123] Compounds described herein can contain one or more double bonds and, thus, potentially give rise to cis/trans (E/Z) isomers, as well as other conformational isomers. Unless stated to the contrary, the invention includes all such possible isomers, as well as mixtures of such isomers. [00124] Unless stated to the contrary, a formula with chemical bonds shown only as solid lines and not as wedges or dashed lines contemplates each possible isomer, e.g., each enantiomer and diastereomer, and a mixture of isomers, such as a racemic or scalemic mixture. Compounds described herein can contain one or more asymmetric centers and, thus, potentially give rise to diastereomers and optical isomers. Unless stated to the contrary, the present invention includes all such possible diastereomers as well as their racemic mixtures, their substantially pure resolved enantiomers, all possible geometric isomers, and pharmaceutically acceptable salts thereof. Mixtures of stereoisomers, as well as isolated specific stereoisomers, are also included. During the course of the synthetic procedures used to prepare such compounds, or in using racemization or epimerization procedures known to those skilled in the art, the products of such procedures can be a mixture of stereoisomers. [00125] Many organic compounds exist in optically active forms having the ability to rotate the plane of plane-polarized light. In describing an optically active compound, the prefixes D and L or R and S are used to denote the absolute configuration of the molecule about its chiral center(s). The prefixes d and l or (+) and (-) are employed to designate the sign of rotation of plane-polarized light by the compound, with (-) or meaning that the compound is levorotatory. A compound prefixed with (+) or d is dextrorotatory. For a given chemical structure, these compounds, called stereoisomers, are identical except that they are non-superimposable mirror Attorney Docket No.37759.0543P1 images of one another. A specific stereoisomer can also be referred to as an enantiomer, and a mixture of such isomers is often called an enantiomeric mixture. A 50:50 mixture of enantiomers is referred to as a racemic mixture. Many of the compounds described herein can have one or more chiral centers and therefore can exist in different enantiomeric forms. If desired, a chiral carbon can be designated with an asterisk (*). When bonds to the chiral carbon are depicted as straight lines in the disclosed formulas, it is understood that both the (R) and (S) configurations of the chiral carbon, and hence both enantiomers and mixtures thereof, are embraced within the formula. As is used in the art, when it is desired to specify the absolute configuration about a chiral carbon, one of the bonds to the chiral carbon can be depicted as a wedge (bonds to atoms above the plane) and the other can be depicted as a series or wedge of short parallel lines is (bonds to atoms below the plane). The Cahn-Ingold-Prelog system can be used to assign the (R) or (S) configuration to a chiral carbon. [00126] When the disclosed compounds contain one chiral center, the compounds exist in two enantiomeric forms. Unless specifically stated to the contrary, a disclosed compound includes both enantiomers and mixtures of enantiomers, such as the specific 50:50 mixture referred to as a racemic mixture. The enantiomers can be resolved by methods known to those skilled in the art, such as formation of diastereoisomeric salts which may be separated, for example, by crystallization (see, CRC Handbook of Optical Resolutions via Diastereomeric Salt Formation by David Kozma (CRC Press, 2001)); formation of diastereoisomeric derivatives or complexes which may be separated, for example, by crystallization, gas-liquid or liquid chromatography; selective reaction of one enantiomer with an enantiomer-specific reagent, for example enzymatic esterification; or gas-liquid or liquid chromatography in a chiral environment, for example on a chiral support for example silica with a bound chiral ligand or in the presence of a chiral solvent. It will be appreciated that where the desired enantiomer is converted into another chemical entity by one of the separation procedures described above, a further step can liberate the desired enantiomeric form. Alternatively, specific enantiomers can be synthesized by asymmetric synthesis using optically active reagents, substrates, catalysts or solvents, or by converting one enantiomer into the other by asymmetric transformation. [00127] Designation of a specific absolute configuration at a chiral carbon in a disclosed compound is understood to mean that the designated enantiomeric form of the compounds can be provided in enantiomeric excess (e.e.). Enantiomeric excess, as used herein, is the presence of a Attorney Docket No.37759.0543P1 particular enantiomer at greater than 50%, for example, greater than 60%, greater than 70%, greater than 75%, greater than 80%, greater than 85%, greater than 90%, greater than 95%, greater than 98%, or greater than 99%. In one aspect, the designated enantiomer is substantially free from the other enantiomer. For example, the “R” forms of the compounds can be substantially free from the “S” forms of the compounds and are, thus, in enantiomeric excess of the “S” forms. Conversely, “S” forms of the compounds can be substantially free of “R” forms of the compounds and are, thus, in enantiomeric excess of the “R” forms. [00128] When a disclosed compound has two or more chiral carbons, it can have more than two optical isomers and can exist in diastereoisomeric forms. For example, when there are two chiral carbons, the compound can have up to four optical isomers and two pairs of enantiomers ((S,S)/(R,R) and (R,S)/(S,R)). The pairs of enantiomers (e.g., (S,S)/(R,R)) are mirror image stereoisomers of one another. The stereoisomers that are not mirror-images (e.g., (S,S) and (R,S)) are diastereomers. The diastereoisomeric pairs can be separated by methods known to those skilled in the art, for example chromatography or crystallization and the individual enantiomers within each pair may be separated as described above. Unless otherwise specifically excluded, a disclosed compound includes each diastereoisomer of such compounds and mixtures thereof. [00129] The compounds according to this disclosure may form prodrugs at hydroxyl or amino functionalities using alkoxy, amino acids, etc., groups as the prodrug forming moieties. For instance, the hydroxymethyl position may form mono-, di- or triphosphates and again these phosphates can form prodrugs. Preparations of such prodrug derivatives are discussed in various literature sources (examples are: Alexander et al., J. Med. Chem.1988, 31, 318; Aligas-Martin et al., PCT WO 2000/041531, p.30). The nitrogen function converted in preparing these derivatives is one (or more) of the nitrogen atoms of a compound of the disclosure. [00130] “Derivatives” of the compounds disclosed herein are pharmaceutically acceptable salts, prodrugs, deuterated forms, radioactively labeled forms, isomers, solvates and combinations thereof. The “combinations” mentioned in this context are refer to derivatives falling within at least two of the groups: pharmaceutically acceptable salts, prodrugs, deuterated forms, radioactively labeled forms, isomers, and solvates. Examples of radioactively labeled forms include compounds labeled with tritium, phosphorous-32, iodine-129, carbon-11, fluorine- 18, and the like. Attorney Docket No.37759.0543P1 [00131] Compounds described herein comprise atoms in both their natural isotopic abundance and in non-natural abundance. The disclosed compounds can be isotopically labeled or isotopically substituted compounds identical to those described, but for the fact that one or more atoms are replaced by an atom having an atomic mass or mass number different from the atomic mass or mass number typically found in nature. Examples of isotopes that can be incorporated into compounds of the invention include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorous, fluorine and chlorine, such as ² H, ³ H, ¹³ C, ¹⁴ C, ¹⁵ N, ¹⁸ O, ¹⁷ O, ³⁵ S, ¹⁸ F and ³⁶ Cl, respectively. Compounds further comprise prodrugs thereof, and pharmaceutically acceptable salts of said compounds or of said prodrugs which contain the aforementioned isotopes and/or other isotopes of other atoms are within the scope of this invention. Certain isotopically labeled compounds of the present invention, for example those into which radioactive isotopes such as ³ H and ¹⁴ C are incorporated, are useful in drug and/or substrate tissue distribution assays. Tritiated, i.e., ³ H, and carbon-14, i.e., ¹⁴ C, isotopes are particularly preferred for their ease of preparation and detectability. Further, substitution with heavier isotopes such as deuterium, i.e., ² H, can afford certain therapeutic advantages resulting from greater metabolic stability, for example increased in vivo half-life or reduced dosage requirements and, hence, may be preferred in some circumstances. Isotopically labeled compounds of the present invention and prodrugs thereof can generally be prepared by carrying out the procedures below, by substituting a readily available isotopically labeled reagent for a non-isotopically labeled reagent. [00132] The compounds described in the invention can be present as a solvate. In some cases, the solvent used to prepare the solvate is an aqueous solution, and the solvate is then often referred to as a hydrate. The compounds can be present as a hydrate, which can be obtained, for example, by crystallization from a solvent or from aqueous solution. In this connection, one, two, three or any arbitrary number of solvent or water molecules can combine with the compounds according to the invention to form solvates and hydrates. Unless stated to the contrary, the invention includes all such possible solvates. [00133] The term “co-crystal” means a physical association of two or more molecules that owe their stability through non-covalent interaction. One or more components of this molecular complex provide a stable framework in the crystalline lattice. In certain instances, the guest molecules are incorporated in the crystalline lattice as anhydrates or solvates, see e.g. “Crystal Engineering of the Composition of Pharmaceutical Phases. Do Pharmaceutical Co-crystals Attorney Docket No.37759.0543P1 Represent a New Path to Improved Medicines?” Almarasson, O., et. al., The Royal Society of Chemistry, 1889-1896, 2004. Examples of co-crystals include p-toluenesulfonic acid and benzenesulfonic acid. [00134] It is also appreciated that certain compounds described herein can be present as an equilibrium of tautomers. For example, ketones with an α-hydrogen can exist in an equilibrium of the keto form and the enol form.

[00135] Likewise, amides with an N-hydrogen can exist in an equilibrium of the amide form and the imidic acid form. As another example, pyrazoles can exist in two tautomeric forms, N¹- unsubstituted, 3-A³ and N¹-unsubstituted, 5-A³ as shown below. Unless stated to the

tautomers. [00136] It is known that chemical substances form solids that are present in different states of order that are termed polymorphic forms or modifications. The different modifications of a polymorphic substance can differ greatly in their physical properties. The compounds according to the invention can be present in different polymorphic forms, with it being possible for particular modifications to be metastable. Unless stated to the contrary, the invention includes all such possible polymorphic forms. [00137] In some aspects, a structure of a compound can be represented by a formula: , which is understood to be equivalent to

,

Attorney Docket No.37759.0543P1 wherein n is typically an integer. That is, Rⁿ is understood to represent five independent substituents, R^n(a), R^n(b), R^n(c), R^n(d), R^n(e). By “independent substituents,” it is meant that each R substituent can be independently defined. For example, if in one instance R^n(a) is halogen, then R^n(b) is not necessarily halogen in that instance. [00138] Certain materials, compounds, compositions, and components disclosed herein can be obtained commercially or readily synthesized using techniques generally known to those of skill in the art. For example, the starting materials and reagents used in preparing the disclosed compounds and compositions are either available from commercial suppliers such as Aldrich Chemical Co., (Milwaukee, Wis.), Acros Organics (Morris Plains, N.J.), Strem Chemicals (Newburyport, MA), Fisher Scientific (Pittsburgh, Pa.), or Sigma (St. Louis, Mo.) or are prepared by methods known to those skilled in the art following procedures set forth in references such as Fieser and Fieser’s Reagents for Organic Synthesis, Volumes 1-17 (John Wiley and Sons, 1991); Rodd’s Chemistry of Carbon Compounds, Volumes 1-5 and supplemental volumes (Elsevier Science Publishers, 1989); Organic Reactions, Volumes 1-40 (John Wiley and Sons, 1991); March’s Advanced Organic Chemistry, (John Wiley and Sons, 4th Edition); and Larock’s Comprehensive Organic Transformations (VCH Publishers Inc., 1989). [00139] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps or operational flow; plain meaning derived from grammatical organization or punctuation; the number or type of embodiments described in the specification. B. COMPOUNDS [00140] In one aspect, the disclosed compounds have a structure represented by a formula: Attorney Docket No.37759.0543P1 , wherein R¹ is selected from R² is selected from hydrogen,

halogen, –CN, –NH2, –OH, –NO2, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1- C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl; wherein each of R³ and R⁴ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1- C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl; or wherein R³ and R⁴ join together to form a ring having 5-7 atoms; wherein each of R⁵ and R⁶ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl; or wherein R⁵ and R⁶ join together to form a ring having 5-7 atoms; and wherein R⁷ is selected from hydrogen, halogen, –CN, –NH2, –OH, –NO2, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1- C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1- C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl; or a pharmaceutically-acceptable salt thereof.. [00141] In a further aspect, R¹ is selected from hydrogen and methyl, ethyl, n-propyl, isopropyl, ethenyl, n-propenyl, isopropenyl, –CH₂F, –CH₂Cl, –CH₂CH₂F, –CH₂CH₂Cl, – CH₂CH₂CH₂F, –CH₂CH₂CH₂Cl, –CH(CH₃)CH₂F, –CH(CH₃)CH₂Cl, –CH₂CN, –CH₂CH₂CN, – CH2CH2CH2CN, –CH(CH3)CH2CN, –CH2OH, –CH2CH2OH, –CH2CH2CH2OH, – CH(CH3)CH2OH, –CH2NH2, –CH2CH2NH2, –CH2CH2CH2NH2, and –CH(CH3)CH2NH2. [00142] In a further aspect, R¹ is C1-C4 alkyl. In a still further aspect, R¹ is selected from methyl, ethyl, n-propyl, and isopropyl. In yet a further aspect, R¹ is selected from methyl and ethyl. In an even further aspect, R¹ is ethyl. In a still further aspect, R¹ is methyl. [00143] In a further aspect, each of R² and R⁷ is independently selected from hydrogen, ‒F, ‒ Cl, ‒Br, ‒I, –CN, –NH₂, –OH, –NO₂, methyl, ethyl, n-propyl, isopropyl, ethenyl, n-propenyl, isopropenyl, –CH2F, –CH2Cl, –CH2CH2F, –CH2CH2Cl, –CH2CH2CH2F, –CH2CH2CH2Cl, – CH(CH₃)CH₂F, –CH(CH₃)CH₂Cl, –CH₂CN, –CH₂CH₂CN, –CH₂CH₂CH₂CN, – Attorney Docket No.37759.0543P1 CH(CH3)CH2CN, –CH2OH, –CH2CH2OH, –CH2CH2CH2OH, –CH(CH3)CH2OH, –OCF3, – OCH2CF3, –OCH2CH2CF3, –OCH(CH3)CF3, –OCH3, –OCH2CH3, –OCH2CH2CH3, – OCH(CH₃)CH₃, –NHCH₃, –NHCH₂CH₃, –NHCH₂CH₂CH₃, –NHCH(CH₃)CH₃, –N(CH₃)₂, – N(CH2CH3)2, –N(CH2CH2CH3)2, –N(CH(CH3)CH3)2, –N(CH3)(CH2CH3), –CH2NH2, – CH2CH2NH2, –CH2CH2CH2NH2, and –CH(CH3)CH2NH2. [00144] In a further aspect, each of R² and R⁷ is hydrogen. [00145] In a further aspect, R³ is selected from hydrogen and C1-C4 alkyl. In a still further aspect, R³ is selected from hydrogen, methyl, ethyl, n-propyl, and isopropyl. In yet a further aspect, R³ is selected from hydrogen, methyl, and ethyl. In an even further aspect, R³ is selected from hydrogen and ethyl. In a still further aspect, R³ is selected from hydrogen and methyl. [00146] In a further aspect, R³ is hydrogen. [00147] In a further aspect, R⁴ is selected from hydrogen and C1-C4 alkyl. In a still further aspect, R⁴ is selected from hydrogen, methyl, ethyl, n-propyl, and isopropyl. In yet a further aspect, R⁴ is selected from hydrogen, methyl, and ethyl. In an even further aspect, R⁴ is selected from hydrogen and ethyl. In a still further aspect, R⁴ is selected from hydrogen and methyl. [00148] In a further aspect, R⁴ is C1-C4 alkyl. In a still further aspect, R⁴ is selected from methyl, ethyl, n-propyl, and isopropyl. In yet a further aspect, R⁴ is selected from methyl and ethyl. In an even further aspect, R⁴ is ethyl. In a still further aspect, R⁴ is methyl. [00149] In a further aspect, each of R⁵ and R⁶ is independently selected from hydrogen, C1- C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl. In a still further aspect, each of R⁵ and R⁶ is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, ethenyl, n-propenyl, isopropenyl, –CH₂F, –CH₂Cl, – CH2CH2F, –CH2CH2Cl, –CH2CH2CH2F, –CH2CH2CH2Cl, –CH(CH3)CH2F, –CH(CH3)CH2Cl, – CH2CN, –CH2CH2CN, –CH2CH2CH2CN, –CH(CH3)CH2CN, –CH2OH, –CH2CH2OH, – CH₂CH₂CH₂OH, –CH(CH₃)CH₂OH, –OCF₃, –OCH₂CF₃, –OCH₂CH₂CF₃, –OCH(CH₃)CF₃, – OCH₃, –OCH₂CH₃, –OCH₂CH₂CH₃, –OCH(CH₃)CH₃, –NHCH₃, –NHCH₂CH₃, – NHCH2CH2CH3, –NHCH(CH3)CH3, –N(CH3)2, –N(CH2CH3)2, –N(CH2CH2CH3)2, – N(CH(CH3)CH3)2, –N(CH3)(CH2CH3), –CH2NH2, –CH2CH2NH2, –CH2CH2CH2NH2, and – CH(CH₃)CH₂NH₂. In yet a further aspect, each of R⁵ and R⁶ is independently selected from hydrogen, methyl, ethyl, ethenyl, –CH2F, –CH2Cl, –CH2CH2F, –CH2CH2Cl, –CH2CN, – Attorney Docket No.37759.0543P1 CH2CH2CN, –CH2OH, –CH2CH2OH, –OCF3, –OCH2CF3, –OCH3, –OCH2CH3, –NHCH3, – NHCH2CH3, –N(CH3)2, –N(CH2CH3)2, –N(CH3)(CH2CH3), –CH2NH2, and –CH2CH2NH2. In an even further aspect, each of R⁵ and R⁶ is independently selected from hydrogen, methyl, –CH₂F, –CH2Cl, –CH2CN, –CH2OH, –OCF3, –OCH3, –NHCH3, –N(CH3)2, and –CH2NH2. [00150] In a further aspect, R⁵ is selected from hydrogen and C1-C4 alkyl. In a still further aspect, R⁵ is selected from hydrogen, methyl, ethyl, n-propyl, and isopropyl. In yet a further aspect, R⁵ is selected from hydrogen, methyl, and ethyl. In an even further aspect, R⁵ is selected from hydrogen and ethyl. In a still further aspect, R⁵ is selected from hydrogen and methyl. [00151] In a further aspect, R⁵ is C1-C4 alkyl. In a still further aspect, R⁵ is selected from methyl, ethyl, n-propyl, and isopropyl. In yet a further aspect, R⁵ is selected from methyl and ethyl. In an even further aspect, R⁵ is ethyl. In a still further aspect, R⁵ is methyl. [00152] In a further aspect, R⁶ is selected from hydrogen and C1-C4 alkyl. In a still further aspect, R⁶ is selected from hydrogen, methyl, ethyl, n-propyl, and isopropyl. In yet a further aspect, R⁶ is selected from hydrogen, methyl, and ethyl. In an even further aspect, R⁶ is selected from hydrogen and ethyl. In a still further aspect, R⁶ is selected from hydrogen and methyl. [00153] In a further aspect, R⁶ is C1-C4 alkyl. In a still further aspect, R⁶ is selected from methyl, ethyl, n-propyl, and isopropyl. In yet a further aspect, R⁶ is selected from methyl and ethyl. In an even further aspect, R⁶ is ethyl. In a still further aspect, R⁶ is methyl. [00154] In a further aspect, each of R³, R⁴, R⁵, and R⁶ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl. In a still further aspect, each of R³, R⁴, R⁵, and R⁶ is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, ethenyl, n-propenyl, isopropenyl, –CH2F, –CH2Cl, –CH2CH2F, –CH2CH2Cl, –CH2CH2CH2F, –CH2CH2CH2Cl, – CH(CH3)CH2F, –CH(CH3)CH2Cl, –CH2CN, –CH2CH2CN, –CH2CH2CH2CN, – CH(CH₃)CH₂CN, –CH₂OH, –CH₂CH₂OH, –CH₂CH₂CH₂OH, –CH(CH₃)CH₂OH, –OCF₃, – OCH₂CF₃, –OCH₂CH₂CF₃, –OCH(CH₃)CF₃, –OCH₃, –OCH₂CH₃, –OCH₂CH₂CH₃, – OCH(CH3)CH3, –NHCH3, –NHCH2CH3, –NHCH2CH2CH3, –NHCH(CH3)CH3, –N(CH3)2, – N(CH2CH3)2, –N(CH2CH2CH3)2, –N(CH(CH3)CH3)2, –N(CH3)(CH2CH3), –CH2NH2, – CH₂CH₂NH₂, –CH₂CH₂CH₂NH₂, and –CH(CH₃)CH₂NH₂. In yet a further aspect, each of R³, R⁴, R⁵, and R⁶ is independently selected from hydrogen, methyl, ethyl, ethenyl, –CH2F, –CH2Cl, Attorney Docket No.37759.0543P1 –CH2CH2F, –CH2CH2Cl, –CH2CN, –CH2CH2CN, –CH2OH, –CH2CH2OH, –OCF3, –OCH2CF3, –OCH3, –OCH2CH3, –NHCH3, –NHCH2CH3, –N(CH3)2, –N(CH2CH3)2, –N(CH3)(CH2CH3), – CH₂NH₂, and –CH₂CH₂NH₂. In an even further aspect, each of R³, R⁴, R⁵, and R⁶ is independently selected from hydrogen, methyl, –CH2F, –CH2Cl, –CH2CN, –CH2OH, –OCF3, – OCH3, –NHCH3, –N(CH3)2, and –CH2NH2. [00155] In another aspect, R³ and R⁴ and/or R⁵ and R⁶ can join together to form a ring having 5-7 atoms. Thus, for example, the compound can be represented by the formula: ,

independently selected from hydrogen, halogen, –CN, –NH2, –OH, –NO2, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl. In a further aspect, each of R⁸ and R⁹ is independently selected from hydrogen, ‒F, ‒Cl, ‒Br, ‒I, –CN, –NH2, –OH, –NO₂, methyl, ethyl, n-propyl, isopropyl, ethenyl, n-propenyl, isopropenyl, –CH₂F, – CH₂Cl, –CH₂CH₂F, –CH₂CH₂Cl, –CH₂CH₂CH₂F, –CH₂CH₂CH₂Cl, –CH(CH₃)CH₂F, – CH(CH3)CH2Cl, –CH2CN, –CH2CH2CN, –CH2CH2CH2CN, –CH(CH3)CH2CN, –CH2OH, – CH2CH2OH, –CH2CH2CH2OH, –CH(CH3)CH2OH, –OCF3, –OCH2CF3, –OCH2CH2CF3, – OCH(CH₃)CF₃, –OCH₃, –OCH₂CH₃, –OCH₂CH₂CH₃, –OCH(CH₃)CH₃, –NHCH₃, – NHCH₂CH₃, –NHCH₂CH₂CH₃, –NHCH(CH₃)CH₃, –N(CH₃)₂, –N(CH₂CH₃)₂, – N(CH2CH2CH3)2, –N(CH(CH3)CH3)2, –N(CH3)(CH2CH3), –CH2NH2, –CH2CH2NH2, – CH₂CH₂CH₂NH₂, and –CH(CH₃)CH₂NH₂. [00156] In one aspect, each of R¹, R⁴, and R⁵ is independently selected from hydrogen, methyl, ethyl, and propyl; each of R² and R⁷ is independently selected from hydrogen and halogen; and each of R³ and R⁶ is hydrogen. [00157] In a further aspect, each of R¹, R⁴, and R⁵ is methyl; each of R² and R⁷ is independently selected from hydrogen and halogen; and each of R³ and R⁶ is hydrogen. Attorney Docket No.37759.0543P1 [00158] In a still further aspect, each of R¹, R⁴, and R⁵ is independently selected from hydrogen, methyl, ethyl, and propyl; and each of R², R³, R⁶, and R⁷ is hydrogen. [00159] In a further aspect, the compound is: , or a pharmaceutically acceptable

[00160] In a further aspect, the compound is: , or a pharmaceutically acceptable

[00161] In a further aspect, the compound is: , or a pharmaceutically acceptable

[00162] In a further aspect, the compound is: , or a pharmaceutically acceptable

Attorney Docket No.37759.0543P1 [00163] In a further aspect, the compound is: , or a pharmaceutically acceptable

[00164] In a further aspect, the compound is: , or a pharmaceutically acceptable

[00165] Non-limiting examples of compounds having hydrogen or C1-C4 substitutions at R¹ include the following. The C1-C4 substituents at R¹, when present, can be optionally substituted as described above. ,

Attorney Docket No.37759.0543P1 . [00166] Non-limiting ^{2 7}

at R and/or R include the following: ,

Attorney Docket No.37759.0543P1

the following: ,

Attorney Docket No.37759.0543P1 [00168]

, ,

Attorney Docket No.37759.0543P1 CN O , ,

Attorney Docket No.37759.0543P1 ,

.

Attorney Docket No.37759.0543P1 [00170] The compound shown above corresponds to a racemic mixture of boldine. Boldine is a naturally-occurring alkaloid present in the leaves and bark of Boldo (Peumus boldus Molina), a tree native to the central region of Chile, among other plants. [00171] In various aspects, the compounds have at least one chiral center and can be substantially free of other isomers (e.g., as a pure or substantially pure optical isomer having a specified activity), or may be admixed, for example, with racemates or other stereoisomers. In one aspect, the compound can be substantially enantiomerically pure. For example, the S enantiomer of boldine can be substantially free of or separated from the R enantiomer of boldine. Similarly, for example, the R enantiomer of boldine can be substantially free of or separated from the S enantiomer of boldine. In one aspect, the compound can be about 80% enantiomerically pure, about 85% enantiomerically pure, about 90% enantiomerically pure, about 91% enantiomerically pure, about 92% enantiomerically pure, about 93% enantiomerically pure, about 94% enantiomerically pure, about 95% enantiomerically pure, about 96% enantiomerically pure, about 97% enantiomerically pure, about 98% enantiomerically pure, about 99% enantiomerically pure, or about 100% enantiomerically pure. [00172] In one exemplary aspect, the compound is represented by the following formula: . The compound shown above is the

(also known by the IUPAC name, (S)-1,10-dimethoxy-6-methyl-5,6,6a,7-tetrahydro-4H-dibenzo[de,g]quinoline-2,9-diol). S- boldine, when present, can be substantially free of other isomers (e.g., as a pure or substantially pure optical isomer having a specified activity), or may be admixed, for example, with racemates or other stereoisomers. In one aspect, S-boldine, when present, can be about 80% enantiomerically pure, about 85% enantiomerically pure, about 90% enantiomerically pure, about 91% enantiomerically pure, about 92% enantiomerically pure, about 93% enantiomerically pure, about 94% enantiomerically pure, about 95% enantiomerically pure, about 96% Attorney Docket No.37759.0543P1 enantiomerically pure, about 97% enantiomerically pure, about 98% enantiomerically pure, about 99% enantiomerically pure, or about 100% enantiomerically pure. [0001] The compounds can be administered to a subject as a pharmaceutically-acceptable salt. Non-limiting examples of pharmaceutically-acceptable salts are mineral acid (hydrochloric acid, hydrobromic acid, phosphoric acid, and the like) salts, organic acid (acetic acid, propionic acid, glutamic acid, citric acid and the like) salts, and quaternary ammonium (methyl iodide, ethyl iodide, and the like) salts. Other non-limiting examples include, but are not limited, to sulfate, citrate, acetate, oxalate, chloride, bromide, iodide, nitrate, bisulfate, phosphate, acid phosphate, phosphonic acid, isonicotinate, lactate, salicylate, citrate, tartrate, oleate, tannate, pantothenate, bitartrate, ascorbate, succinate, maleate, gentisinate, fumarate, gluconate, glucaronate, saccharate, formate, benzoate, glutamate, methanesulfonate, ethanesulfonate, benzenesulfonate, p-toluenesulfonate, and pamoate (i.e., 1,1’-methylene-bis-(2-hydroxy-3-naphthoate)) salts. Still other salts include, but are not limited to, salts with inorganic bases including alkali metal salts such as sodium salts, and potassium salts; alkaline earth metal salts such as calcium salts, and magnesium salts; aluminum salts; and ammonium salts. Other salts with organic bases include salts with diethylamine, diethanolamine, meglumine, and N,N'-dibenzylethylenediamine. It is understood that the pharmaceutically acceptable salts are non-toxic. Additional information on suitable pharmaceutically acceptable salts can be found in Remington’s Pharmaceutical Sciences, 17th ed., Mack Publishing Company, Easton, Pa., 1985, which is incorporated herein by reference. [00173] Pharmaceutically-acceptable salts of the compounds can be salts formed with bases, namely cationic salts such as alkali and alkaline earth metal salts, such as sodium, lithium, potassium, calcium, magnesium, as well as ammonium salts, such as ammonium, trimethyl- ammonium, diethylammonium, and tris-(hydroxymethyl)-methyl-ammonium salts. Similarly, acid addition salts, such as mineral acids, organic carboxylic and organic sulfonic acids, e.g., hydrochloric acid, methanesulfonic acid, maleic acid, are also contemplated. Neutral forms of boldine and its analogs can be regenerated by contacting the salt with a base or acid and isolating the parent compound in a conventional manner. [00174] In one aspect, the disclosed compound is S-boldine hydrochloride. S-Boldine hydrochloride can be prepared from Boldo’s bark, as described in A. Urzúa and P. Acuña, Attorney Docket No.37759.0543P1 “Alkaloids from the bar of Peumus boldus,” Fitoterapia, vol.54, no.4, pp.175-177, 1983, which is incorporated herein by reference. [00175] Pharmaceutical Compositions [00176] In various aspects, the compounds can be administered to a subject as a composition or formulation comprising a pharmaceutically-acceptable carrier. Non-limiting examples of suitable aqueous and nonaqueous carriers, diluents, solvents or vehicles include water, ethanol, polyols (such as glycerol, propylene glycol, polyethylene glycol and the like), carboxymethylcellulose and suitable mixtures thereof, vegetable oils (such as olive oil) and injectable organic esters such as ethyl oleate. Proper fluidity can be maintained, for example, by the use of coating materials such as lecithin, by the maintenance of the required particle size in the case of dispersions and by the use of surfactants. [00177] Pharmaceutically-acceptable carries can also comprise adjuvants such as preservatives, wetting agents, emulsifying agents and dispersing agents. Prevention of the action of microorganisms can be ensured by the inclusion of various antibacterial and antifungal agents such as paraben, chlorobutanol, phenol, sorbic acid and the like. It can also be desirable to include isotonic agents such as sugars, sodium chloride and the like. Prolonged absorption of the injectable pharmaceutical form can be brought about by the inclusion of agents, such as aluminum monostearate and gelatin, which delay absorption. Injectable depot forms can be made by forming microencapsule matrices of the compounds in biodegradable polymers such as polylactide-polyglycolide, poly(orthoesters) and poly(anhydrides). Depending upon the ratio of drug to polymer and the nature of the particular polymer employed, the rate of drug release can be controlled. Depot injectable formulations can also be prepared by entrapping the drug in liposomes or microemulsions which are compatible with body tissues. The injectable formulations can be sterilized, for example, by filtration through a bacterial-retaining filter or by incorporating sterilizing agents in the form of sterile solid compositions which can be dissolved or dispersed in sterile water or other sterile injectable media just prior to use. Suitable inert carriers can include sugars such as lactose. [00178] In some aspects, the pharmaceutically-acceptable carrier can include an excipient. Suitable excipients include, without limitation, saccharides, for example, glucose, lactose, or sucrose, mannitol, or sorbitol, cellulose derivatives, and/or calcium phosphate, for example, tricalcium phosphate or acidic calcium phosphate. Attorney Docket No.37759.0543P1 [00179] In further aspects, the pharmaceutically-acceptable carrier can include a binder. Suitable binders include, without limitation, tare compounds such as starch paste, for example, corn, wheat, rice, and potato starch, gelatin, tragacanth, methylcellulose, hydroxypropyl methylcellulose, carboxymethylcellulose, and/or polyvinylpyrrolidone. In still further aspects, there can be a disintegrating agent, such as the aforementioned starches and carboxymethyl starch, crosslinked polyvinylpyrrolidone, agar, or alginic acid or a salt thereof, such as sodium alginate. [00180] In some aspects, the pharmaceutically-acceptable carrier can include an additive. Examples of additives include, but are not limited to, diluents, buffers, binders, surface-active agents, lubricants, humectants, pH adjusting agents, preservatives (including anti-oxidants), emulsifiers, occlusive agents, opacifiers, antioxidants, colorants, flavoring agents, gelling agents, thickening agents, stabilizers, and surfactants, among others. Thus, in various further aspects, the additive is vitamin E, gum acacia, citric acid, stevia extract powder, Luo Han Gou, Monoammonium Glycyrhizinate, Ammonium Glycyrrhizinate, honey, or combinations thereof. In a still further aspect, the additive is a flavoring agent, a binder, a disintegrant, a bulking agent, or silica. In a further aspect, the additive can include flowability-control agents and lubricants, such as silicon dioxide, talc, stearic acid and salts thereof, such as magnesium stearate or calcium stearate, and/or propylene glycol. [00181] In various aspects, when the compounds are formulated for oral use, such as for example, a tablet, pill, or capsule, the composition can include a coating layer that is resistant to gastric acid. Such a layer, in various aspects, can include a concentrated solution of saccharides that can comprise gum arabic, talc, polyvinylpyrrolidone, polyethylene glycol, and/or titanium dioxide, and suitable organic solvents or salts thereof. [00182] Dosage forms can comprise the compounds or a pharmaceutically-acceptable salt thereof, together in combination with a pharmaceutically acceptable excipient, such as a preservative, buffer, saline, or phosphate buffered saline. Dosage forms can be made using conventional pharmaceutical manufacturing and compounding techniques. Dosage forms can comprise inorganic or organic buffers (e.g., sodium or potassium salts of phosphate, carbonate, acetate, or citrate) and pH adjustment agents (e.g., hydrochloric acid, sodium or potassium hydroxide, salts of citrate or acetate, amino acids and their salts) antioxidants (e.g., ascorbic acid, alpha-tocopherol), surfactants (e.g., polysorbate 20, polysorbate 80, polyoxyethylene9-10 nonyl Attorney Docket No.37759.0543P1 phenol, sodium desoxycholate), solution and/or cryo/lyo stabilizers (e.g., sucrose, lactose, mannitol, trehalose), osmotic adjustment agents (e.g., salts or sugars), antibacterial agents (e.g., benzoic acid, phenol, gentamicin), antifoaming agents (e.g., polydimethylsilozone), preservatives (e.g., thimerosal, 2-phenoxyethanol, EDTA), polymeric stabilizers and viscosity-adjustment agents (e.g., polyvinylpyrrolidone, poloxamer 488, carboxymethylcellulose) and co-solvents (e.g., glycerol, polyethylene glycol, ethanol). A dosage form formulated for injectable use can have a disclosed composition or a product of a disclosed method of making, suspended in sterile saline solution for injection together with a preservative. C. M^{ETHODS OF} M^{AKING THE} C^OMPOUNDS [00183] The compounds of this invention can be obtained from a natural source, e.g., a plant or component thereof that naturally produces alkaloids such as those described herein, or can be prepared by employing reactions as shown in the following schemes, in addition to other standard manipulations that are known in the literature, exemplified in the experimental sections or clear to one skilled in the art. For clarity, examples having a single substituent are shown where multiple substituents are allowed under the definitions disclosed herein. [00184] Reactions used to generate the compounds of this invention are prepared by employing reactions as shown in the following Reaction Schemes, as described and exemplified below. In certain specific examples, the disclosed compounds can be prepared by Routes I-IV, as described and exemplified below. The following examples are provided so that the invention might be more fully understood, are illustrative only, and should not be construed as limiting. 1. ROUTE I [00185] In one aspect, the disclosed compounds can be prepared according to the oxidative coupling reaction shown in Scheme 1A and Scheme 1B.

Attorney Docket No.37759.0543P1 SCHEME 1A.

water, or a combination thereof, and subjected to oxidative coupling using a strong Lewis acid such as ferric chloride (FeCl3) with a suitable acid such as hydrochloric acid. Following the coupling reaction, the resulting salts (2) can be converted to the neutral compounds (3) if desired using a suitable base. SCHEME 1B.

, which have at least one unsubstituted phenolic functional group. Salts (5) can be reduced to neutral form (6) using a suitable base. The unsubstituted phenolic groups can be further substituted as desired. 2. ROUTE II [00188] According to one aspect, compounds (6) can be further substituted at one or more phenolic hydroxyl groups according to Scheme 2. A suitable quaternary ammonium salt such as 7 shown below can be dissolved in a suitable solvent such as methanol with a suitable base such as potassium hydroxide to give the corresponding substituted compounds (8). Attorney Docket No.37759.0543P1 SCHEME 2.

[00189] According to one aspect, compounds in which R³ and R⁴ and/or R⁵ and R⁶ join together to form a ring having 5-7 atoms can be prepared according to methods known in the art. In one aspect, such compounds can be prepared by nucleophilic substitution reactions such as the one shown below in Scheme 3. S^CHEME 3. R⁸ [00190]

weak base such as potassium carbonate, with the addition of potassium iodide, in a suitable solvent such as dimethylformamide. According to one aspect, the reaction shown above can be carried out at a suitable temperature, e.g., 105-120 °C, for a suitable time, e.g., 1-12 hours. Other methods of preparing compounds in which R³ and R⁴ and/or R⁵ and R⁶ join together to form a ring having 5-7 atoms will be recognized by those skilled in the art. 4. R^OUTE IV Attorney Docket No.37759.0543P1 [00191] In a further aspect, compounds with halogen substitutions at R² and/or R⁷ can be prepared according to methods known in the art, such as the exemplary reaction Scheme 4. S^CHEME 4. [00192]

using trifluoroacetic acid and a suitable reagent such as N-bromosuccinimide for a suitable time such as 1-3 hours at room temperature to give compounds of type (13). Scheme 4 can be tailored as one of skill will appreciate to prepare various halogen substitution patterns on the aromatic rings. D. METHODS OF TREATING PERIPHERAL NERVE INJURY IN A SUBJECT [00193] In one aspect, disclosed is a method of treating or preventing a peripheral nerve injury in a subject in need thereof, the method comprising administering to the subject an effective amount of a compound having a structure represented by a formula: , herein R¹

w is selected from R² is selected from hydrogen, halogen, –CN, –NH₂, –OH, –NO₂, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1- C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl; wherein each of R³ and R⁴ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1- C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) Attorney Docket No.37759.0543P1 dialkylamino, and C1-C4 aminoalkyl, or wherein R³ and R⁴ join together to form a ring having 5-7 atoms; wherein each of R⁵ and R⁶ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl, or wherein R⁵ and R⁶ join together to form a ring having 5-7 atoms; and wherein R⁷ is selected from hydrogen, halogen, –CN, –NH₂, –OH, –NO₂, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1- C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1- C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl; or a pharmaceutically acceptable salt thereof, wherein the administering step occurs less than one week after the acute nervous system. [00194] In a further aspect, R¹ is C1-C4 alkyl. In a still further aspect, R¹ is methyl. [00195] In a further aspect, each of R² and R⁷ is hydrogen. [00196] In a further aspect, each of R³ and R⁴ is independently selected from hydrogen, C1- C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl. [00197] In a further aspect, R³ is selected from hydrogen and C1-C4 alkyl. In a still further aspect, R³ is hydrogen. [00198] In a further aspect, R⁴ is selected from hydrogen and C1-C4 alkyl. In a still further aspect, R⁴ is C1-C4 alkyl. In yet a further aspect, R⁴ is methyl. [00199] In a further aspect, each of R⁵ and R⁶ is independently selected from hydrogen, C1- C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl. [00200] In a further aspect, R⁵ is selected from hydrogen and C1-C4 alkyl. In a still further aspect, R⁵ is C1-C4 alkyl. In yet a further aspect, R⁵ is methyl. [00201] In a further aspect, R⁶ is selected from hydrogen and C1-C4 alkyl. In a still further aspect, R⁶ is hydrogen. [00202] In a further aspect, each of R¹, R⁴, and R⁵ is independently selected from hydrogen, methyl, ethyl, and propyl; wherein each of R² and R⁷ is independently selected from hydrogen and halogen; and wherein each of R³ and R⁶ is hydrogen. Attorney Docket No.37759.0543P1 [00203] In a further aspect, each of R¹, R⁴, and R⁵ is methyl; wherein each of R² and R⁷ is independently selected from hydrogen and halogen; and wherein each of R³ and R⁶ is hydrogen. [00204] In a further aspect, each of R¹, R⁴, and R⁵ is independently selected from hydrogen, methyl, ethyl, and propyl; and wherein each of R², R³, R⁶, and R⁷ is hydrogen. [00205] In a further aspect, the compound is: , or a pharmaceutically acceptable

[00206] In a further aspect, the compound is: , or a pharmaceutically acceptable

[00207] In a further aspect, the compound is: ,

or a pharmaceutically acceptable [00208] In a further aspect, the compound is: Attorney Docket No.37759.0543P1 , or a pharmaceutically acceptable

[00209] In a further aspect, the compound is: , or a pharmaceutically acceptable

[00210] In a further aspect, the compound is: , or a pharmaceutically acceptable

[00211] As detailed herein, administration of the compound can be used to slow, prevent, or otherwise treat a peripheral nerve injury. Thus, in various aspects, the effective amount is a therapeutically effective amount. In a further aspect, the peripheral nerve injury is due to an iatrogenic injury or a non-iatrogenic injury, and the administering step occurs at a time point or time period thereafter. For example, in various aspects, the peripheral nerve injury is due to an iatrogenic injury, and the administering step occurs from about 30 minutes before the procedure in the case of radiation therapy or at the time of injury in non-radiation cases to about one week after the iatrogenic injury. In a still further aspect, the peripheral nerve injury is due to a non- Attorney Docket No.37759.0543P1 iatrogenic injury, and the administering step occurs from diagnosis until there are early signs of reinnervation. [00212] As detailed herein, administration of the compound can beneficially prolong the time period within which surgical repair of an injured or severed nerve can be repaired. For example, a peripheral nerve injury can be treated as long as about 24 hours after injury, as long as about 2 days after injury, as long as about 5 days after injury, as long as about one week after injury, as long as about two weeks after injury, as long as about one month after injury, as long as about three months after injury, as long as about six months after injury, as long as about one year after injury, or longer than about one year after injury. [00213] In various aspects, the effective amount is a prophylactically effective amount. Thus, in various aspects, the subject does not have a peripheral nerve injury at the time of administration (i.e., the subject does not currently have a peripheral nerve injury). In a further aspect, the subject is at risk for receiving a peripheral nerve injury. For example, the subject can be undergoing a medical procedure for which a peripheral nerve injury is a possible side effect, wherein the medical procedure is to occur no more than about 30 minutes to 72 hours after the administering step. Exemplary medical procedures for which a peripheral nerve injury is a possible side effect include, but are not limited to, a tumor resection, head and neck surgery, facial reconstruction, orthognathic surgery, tooth extraction, fracture fixation, joint arthroplasty, knee arthroscopy and ligament reconstruction, wound debridement, insertion or removal of orthopedic hardware, nerve decompression, tenotomy, or laminectomy. [00214] As detailed herein, the compound can be administered prophylactically (e.g., for a “planned” nerve injury such as, for example, a nerve injury due to a tumor resection), administered simultaneously or approximately simultaneously with the injury (e.g., at the time of injury such as, for example, an iatrogenic injury), or administered at a time period following the injury or trauma. [00215] In various aspects, the compound is administered to the subject via oral, parenteral, or intramuscular administration. In a further aspect, the compound is administered to the subject via oral administration. In a still further, aspect the compound is administered to the subject via parenteral administration (e.g., intravenous administration). In yet a further aspect, the compound is administered to the subject via intramuscular administration. Attorney Docket No.37759.0543P1 [00216] In various aspects, the compound is administered to the subject via local administration. [00217] In various aspects the compound is administered as a single dose. In various further aspects, the compound is repeatedly administered over a time period of, for example, a period of days, weeks, or months. In various further aspects, the amount of the compound administered is tapered off or decreased over time relative to the initial amount of the compound administered. [00218] In various aspects, the subject is a mammal. In a further aspect, the subject is a human. [00219] In various aspects, treating promotes neuromuscular recovery. As would be understood by one of ordinary skill in the art, neuromuscular recovery can be measured as a percent of expected strength that is recovered. For example, with respect to a hand injury, the grip strength of an injured hand can be measured after administration of the compound, and compared to the grip strength of the non-injured (contralateral) hand, i.e., the normal reference for that individual. Alternatively, the grip strength of an injured hand can be measured after administration of the compound, and then measured again one week, two weeks, or more than two weeks after administration to see whether an improvement is realized. Neuromuscular recovery of injuries to alternative body parts can be similarly assessed. Thus, in a further aspect, neuromuscular recovery is demonstrated by an improvement of at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 99%, or greater than 99% in recovered expected strength. [00220] In various aspects, treating promotes improved sensation. As would be understood by one of ordinary skill in the art, sensation can be measured using standard neurological exams, such as, for example, sensation of pin prick, vibration, and temperature (i.e., hot and cold). Thus, in a further aspect, improved sensation is demonstrated by a score of 2 points or higher on a 1-5 scale in a sensation neurological exam. [00221] In various aspects, treating decreases atrophied muscle volume. As would be understood by one of ordinary skill in the art, atrophied muscle volume can be determined using ultrasound imagery. For example, ultrasound imagery can be used to measure the volume of the atrophied muscle and compared to the volume of the muscle on the contralateral side. Thus, in a further aspect, an improvement in atrophied muscle volume is demonstrated by a decrease of 20%, a decrease of 30%, a decrease of 40%, a decrease of 50%, a decrease of 60%, a decrease of Attorney Docket No.37759.0543P1 70%, or a decrease of greater than 70% in the volume (or circumference) of atrophied muscle compared to the volume of a reference non-atrophied muscle on the subject’s contralateral side. [00222] Alternative techniques for guiding treatment protocol (e.g., time course of administration) include, but are not limited to, nerve and muscle electrophysiological measurements (e.g., conduction speed, amplitude). E. M^{ETHODS OF} T^REATING D^ENERVATION-I^NDUCED M^USCULAR A^{TROPHY IN A} S^UBJECT [00223] In one aspect, disclosed is a method of treating or preventing a denervation-induced muscular atrophy in a subject in need thereof, the method comprising administering to the subject an effective amount of a compound having a structure represented by a formula: , wherein R¹ is selected from

R² is selected from hydrogen, halogen, –CN, –NH₂, –OH, –NO₂, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1- C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl; wherein each of R³ and R⁴ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1- C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl, or wherein R³ and R⁴ join together to form a ring having 5-7 atoms; wherein each of R⁵ and R⁶ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl, or wherein R⁵ and R⁶ join together to form a ring having 5-7 atoms; and wherein R⁷ is selected from hydrogen, halogen, –CN, –NH2, –OH, –NO2, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1- C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1- C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl, or a pharmaceutically acceptable salt thereof. [00224] In a further aspect, R¹ is C1-C4 alkyl. In a still further aspect, R¹ is methyl. Attorney Docket No.37759.0543P1 [00225] In a further aspect, each of R² and R⁷ is hydrogen. [00226] In a further aspect, each of R³ and R⁴ is independently selected from hydrogen, C1- C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl. [00227] In a further aspect, R³ is selected from hydrogen and C1-C4 alkyl. In a still further aspect, R³ is hydrogen. [00228] In a further aspect, R⁴ is selected from hydrogen and C1-C4 alkyl. In a still further aspect, R⁴ is C1-C4 alkyl. In yet a further aspect, R⁴ is methyl. [00229] In a further aspect, each of R⁵ and R⁶ is independently selected from hydrogen, C1- C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl. [00230] In a further aspect, R⁵ is selected from hydrogen and C1-C4 alkyl. In a still further aspect, R⁵ is C1-C4 alkyl. In yet a further aspect, R⁵ is methyl. [00231] In a further aspect, R⁶ is selected from hydrogen and C1-C4 alkyl. In a still further aspect, R⁶ is hydrogen. [00232] In a further aspect, each of R¹, R⁴, and R⁵ is independently selected from hydrogen, methyl, ethyl, and propyl; wherein each of R² and R⁷ is independently selected from hydrogen and halogen; and wherein each of R³ and R⁶ is hydrogen. [00233] In a further aspect, each of R¹, R⁴, and R⁵ is methyl; wherein each of R² and R⁷ is independently selected from hydrogen and halogen; and wherein each of R³ and R⁶ is hydrogen. [00234] In a further aspect, each of R¹, R⁴, and R⁵ is independently selected from hydrogen, methyl, ethyl, and propyl; and wherein each of R², R³, R⁶, and R⁷ is hydrogen. [00235] In a further aspect, the compound is: ,

Attorney Docket No.37759.0543P1 or a pharmaceutically acceptable salt thereof. [00236] In a further aspect, the compound is: , or a pharmaceutically acceptable

[00237] In a further aspect, the compound is: , or a pharmaceutically acceptable

[00238] In a further aspect, the compound is: ,

or a pharmaceutically acceptable [00239] In a further aspect, the compound is: ,

Attorney Docket No.37759.0543P1 or a pharmaceutically acceptable salt thereof. [00240] In a further aspect, the compound is: , or a pharmaceutically acceptable

[00241] In various aspects, the denervation-induced muscular atrophy is due to trauma, an autoimmune disorder, or a viral infection. In a further aspect, the denervation-induced muscular atrophy is due to nerve injury or nerve transection. In a still further aspect, the denervation- induced muscular atrophy is due to diabetic neuropathy, degenerative disc disease, alcoholic neuropathy, pernicious anemia, amyotrophic lateral sclerosis (ALS), Guillain-Barré syndrome, spinal muscular atrophy, or Charcot-Marie-Tooth disease. [00242] As detailed herein, administration of the compound can be used to slow, prevent, or otherwise treat a denervation-induced muscular atrophy. Thus, in various aspects, the effective amount is a therapeutically effective amount. In a further aspect, the denervation-induced muscular atrophy is due to an iatrogenic injury or a non-iatrogenic injury, and the administering step occurs at a time point or time period thereafter. For example, in various aspects, the denervation-induced muscular atrophy is due to an iatrogenic injury, and the administering step occurs from about 30 minutes to about one year after the iaotrogenic injury. In a still further aspect, the denervation-induced muscular atrophy is due to a non-iatrogenic injury, and the administering step occurs from about 30 minutes to about one year (e.g., 30 minutes, 3 months, 6 months, one year) after the non-iaotrogenic injury. In yet a further aspect, the denervation- induced muscular atrophy is due to a non-iatrogenic injury, and the administering step occurs greater than one year after the non-iatrogenic injury. [00243] As detailed herein, administration of the compound can beneficially prolong the time period within which surgical repair of a nerve suffering from denervation-induced muscular atrophy can be repaired. For example, denervation-induced muscular atrophy can be treated as long as about 24 hours after injury, as long as about 2 days after injury, as long as about 5 days Attorney Docket No.37759.0543P1 after injury, as long as about one week after injury, as long as about two weeks after injury, as long as about one month after injury, as long as about three months after injury, as long as about six months after injury, as long as about one year after injury; or longer than about one year after injury. [00244] In various aspects, the effective amount is a prophylactically effective amount. Thus, in various aspects, the subject does not have denervation-induced muscular atrophy at the time of administration (i.e., the subject does not currently have denervation-induced muscular atrophy). In a further aspect, the subject is at risk for developing denervation-induced muscular atrophy. For example, the subject can be undergoing a medical procedure for which a peripheral nerve injury and/or denervation-induced muscular atrophy is a possible side effect, wherein the medical procedure is to occur no more than about 30 minutes to 72 hours (e.g, 30 minutes to 72 hours, 30 minutes to 60 hours, 30 minutes to 48 hours, 30 minutes to 36 hours, 30 minutes to 24 hours, 30 minutes to 12 hours, 30 minutes to 6 hours, 30 minutes to 3 hours, 30 minutes to 1 hour, 1 hour to 72 hours, 3 hours to 72 hours, 6 hours to 72 hours, 12 hours to 72 hours, 24 hours to 72 hours, 36 hours to 72 hours, 48 hours to 72 hours, 60 hours to 72 hours, 1 hour to 60 hours, 3 hours to 48 hours, 6 hours to 36 hours, 12 hours to 24 hours) after the administering step. Exemplary medical procedures for which a peripheral nerve injury and/or denervation-induced muscular atrophy is a possible side effect include, but are not limited to, a tumor resection, head and neck surgery, facial reconstruction, chest surgery orthognathic surgery, tooth extraction, fracture fixation, joint arthroplasty, knee arthroscopy and ligament reconstruction, wound debridement, insertion or removal of orthopedic hardware, nerve decompression, tenotomy, or laminectomy. [00245] As detailed herein, the compound can be administered prophylactically (e.g., for a “planned” nerve injury such as, for example, a nerve injury due to a tumor resection), administered simultaneously or approximately simultaneously with the injury (e.g., at the time of injury such as, for example, an iatrogenic injury), or administered at a time period following the injury or trauma. [00246] In various aspects, the compound is administered to the subject via oral, parenteral, or intramuscular administration. In a further aspect, the compound is administered to the subject via oral administration. In a still further aspect, the compound is administered to the subject via Attorney Docket No.37759.0543P1 parenteral administration (e.g., intravenous administration). In yet a further aspect, the compound is administered to the subject via intramuscular administration. [00247] In various aspects, the compound is administered to the subject via local administration. [00248] In various aspects the compound is administered as a single dose. In various further aspects, the compound is repeatedly administered over a time period of, for example, a period of days, weeks, or months. In various further aspects, the amount of the compound administered is tapered off or decreased over time relative to the initial amount of the compound administered. [00249] In various aspects, the subject is a mammal. In a further aspect, the subject is a human. [00250] In various aspects, the subject has been diagnosed with a need for treatment of denervation-induced muscular atrophy prior to the administering step. [00251] In various aspects, the subject has been diagnosed with a need for prevention of denervation-induced muscular atrophy prior to the administering step. [00252] In various aspects, the subject has previously suffered a nerve injury or transection. In a further aspect the subject has previously suffered a nerve injury or transection at least 18 months prior to the administering step. In a further aspect the subject has previously suffered a nerve injury or transection at least 24 months prior to the administering step. In a further aspect the subject has previously suffered a nerve injury or transection more than 24 months prior to the administering step. [00253] In various aspects, the method further comprising the step of identifying a subject in need of treatment or prevention of denervation-induced muscular atrophy. F. A^DDITIONAL M^{ETHODS OF} U^{SING THE} C^OMPOUNDS [00254] In one aspect, the disclosed compounds and pharmaceutical compositions are useful in treating or preventing a peripheral nerve injury as further described herein. In one aspect, the disclosed compounds and pharmaceutical compositions are useful in treating or preventing denervation-induced muscular atrophy as further described herein. [00255] Thus, in various aspects, the disclosed compounds and pharmaceutical compositions are useful to preserve an evoked muscle response up to 2 weeks following transection of prolonged denervation. In a further aspect, the disclosed compounds and pharmaceutical Attorney Docket No.37759.0543P1 compositions are useful in reducing intramuscular connexin 43/45 expression and muscle fiber atrophy up to 4 weeks following denervation. In a still further aspect, the disclosed compounds and pharmaceutical compositions are useful in preventing connexin 43 hemichannel formation on denervated Schwann cells up to 4 weeks post injury. In yet a further aspect, the disclosed compounds and pharmaceutical compositions are useful in improvingmuscle and nerve electrophysiological response following denervation and delayed nerve repair. Examples of conditions associated with such membrane channels include, but are not limited to, denervation- induced muscular atrophy and peripheral nerve injuries. [00256] To treat or control the condition, the compounds and pharmaceutical compositions comprising the compounds are administered to a subject in need thereof, such as a vertebrate, e.g., a mammal, a fish, a bird, a reptile, or an amphibian. The subject can be a human, non- human primate, horse, pig, rabbit, dog, sheep, goat, cow, cat, guinea pig or rodent. The term does not denote a particular age or sex. Thus, adult and newborn subjects, as well as fetuses, whether male or female, are intended to be covered. The subject is preferably a mammal, such as a human. Prior to administering the compounds or compositions, the subject can be diagnosed with a need for treatment of a condition associated with Cx43 and Cx45 dysfunction such as, for example, denervation-induced muscular atrophy and peripheral nerve injuries. [00257] The compounds or compositions can be administered to the subject according to any method. Such methods are well known to those skilled in the art and include, but are not limited to, oral administration, transdermal administration, administration by inhalation, nasal administration, topical administration, intravaginal administration, ophthalmic administration, intraaural administration, intracerebral administration, rectal administration, sublingual administration, buccal administration and parenteral administration, including injectable such as intravenous administration, intra-arterial administration, intramuscular administration, and subcutaneous administration. Administration can be continuous or intermittent. A preparation can be administered therapeutically; that is, administered to treat an existing disease or condition. A preparation can also be administered prophylactically; that is, administered for prevention of a condition associated with Cx43 and Cx45 dysfunction such as, for example, denervation-induced muscular atrophy and peripheral nerve injuries. [00258] The therapeutically effective amount or dosage of the compound can vary within wide limits. Such a dosage is adjusted to the individual requirements in each particular case Attorney Docket No.37759.0543P1 including the specific compound(s) being administered, the route of administration, the condition being treated, as well as the patient being treated. In general, in the case of oral or parenteral administration to adult humans weighing approximately 70 Kg or more, a daily dosage of about 10 mg to about 10,000 mg, preferably from about 200 mg to about 1,000 mg, should be appropriate, although the upper limit may be exceeded. The daily dosage can be administered as a single dose or in divided doses, or for parenteral administration, as a continuous infusion. Single dose compositions can contain such amounts or submultiples thereof of the compound or composition to make up the daily dose. The dosage can be adjusted by the individual physician in the event of any contraindications. Dosage can vary, and can be administered in one or more dose administrations daily, for one or several days. 1. USE OF COMPOUNDS [00259] In one aspect, the invention relates to the use of a disclosed compound or a product of a disclosed method. In a further aspect, a use relates to the manufacture of a medicament for the treatment of a condition associated with Cx43 and Cx50 dysfunction such as, for example, denervation-induced muscular atrophy and peripheral nerve injuries. [00260] Also provided are the uses of the disclosed compounds and products. In one aspect, the invention relates to use of at least one disclosed compound; or a pharmaceutically acceptable salt, hydrate, solvate, or polymorph thereof. In a further aspect, the compound used is a product of a disclosed method of making. [00261] In a further aspect, the use relates to a process for preparing a pharmaceutical composition comprising a therapeutically effective amount of a disclosed compound or a product of a disclosed method of making, or a pharmaceutically acceptable salt, solvate, or polymorph thereof, for use as a medicament. [00262] In a further aspect, the use relates to a process for preparing a pharmaceutical composition comprising a therapeutically effective amount of a disclosed compound or a product of a disclosed method of making, or a pharmaceutically acceptable salt, solvate, or polymorph thereof, wherein a pharmaceutically acceptable carrier is intimately mixed with a therapeutically effective amount of the compound or the product of a disclosed method of making. [00263] In various aspects, the use relates to a treatment of a condition associated with Cx43 and Cx45 signaling dysfunction in a subject. In one aspect, the use is characterized in that the Attorney Docket No.37759.0543P1 subject is a human. In one aspect, the use is characterized in that the condition associated with Cx43 and Cx45 expression is linked to adverse effects on the reinnervation process and blocking them slows the progression of muscle atrophy following denervation. In a further aspect, the use is characterized in that the condition associated with Cx43 and Cx45 expression can be used to prevent the harmful consequences of denervation without causing permanent damage to the intrinsic processes involved in muscle regeneration. [00264] In a further aspect, the use relates to the manufacture of a medicament for the treatment of a condition associated with Cx43 and Cx45 signaling dysfunction in a subject. [00265] It is understood that the disclosed uses can be employed in connection with the disclosed compounds, products of disclosed methods of making, methods, compositions, and kits. In a further aspect, the invention relates to the use of a disclosed compound or a disclosed product in the manufacture of a medicament for the treatment of a condition associated with Cx43 and Cx45 expression in a mammal. In a further aspect, the condition associated with Cx43 and Cx45 expression such as, for example, denervation-induced muscular atrophy and peripheral nerve injuries. 2. M^{ANUFACTURE OF A} M^EDICAMENT [00266] In one aspect, the invention relates to a method for the manufacture of a medicament for treating a condition associated with Cx43 and Cx45 signaling dysfunction in a subject having the condition, the method comprising combining a therapeutically effective amount of a disclosed compound or product of a disclosed method with a pharmaceutically acceptable carrier or diluent. [00267] As regards these applications, the present method includes the administration to an animal, particularly a mammal, and more particularly a human, of a therapeutically effective amount of the compound effective in the treatment of a condition associated with Cx43 and Cx50 dysfunction such as, for example, denervation-induced muscular atrophy and peripheral nerve injuries. The dose administered to an animal, particularly a human, in the context of the present invention should be sufficient to affect a therapeutic response in the animal over a reasonable timeframe. One skilled in the art will recognize that dosage will depend upon a variety of factors including the condition of the animal and the body weight of the animal. Attorney Docket No.37759.0543P1 [00268] The total amount of the compound of the present disclosure administered in a typical treatment is preferably between about 0.05 mg/kg and about 100 mg/kg of body weight for mice, and more preferably between 0.05 mg/kg and about 50 mg/kg of body weight for mice, and between about 100 mg/kg and about 500 mg/kg of body weight for humans, and more preferably between 200 mg/kg and about 400 mg/kg of body weight for humans per daily dose. This total amount is typically, but not necessarily, administered as a series of smaller doses over a period of about one time per day to about three times per day for about 24 months, and preferably over a period of twice per day for about 12 months. [00269] The size of the dose also will be determined by the route, timing and frequency of administration as well as the existence, nature and extent of any adverse side effects that might accompany the administration of the compound and the desired physiological effect. It will be appreciated by one of skill in the art that various conditions or disease states, in particular chronic conditions or disease states, may require prolonged treatment involving multiple administrations. [00270] Thus, in one aspect, the invention relates to the manufacture of a medicament comprising combining a disclosed compound or a product of a disclosed method of making, or a pharmaceutically acceptable salt, solvate, or polymorph thereof, with a pharmaceutically acceptable carrier or diluent. [00271] The foregoing description illustrates and describes the disclosure. Additionally, the disclosure shows and describes only the preferred embodiments but, as mentioned above, it is to be understood that it is capable to use in various other combinations, modifications, and environments and is capable of changes or modifications within the scope of the invention concepts as expressed herein, commensurate with the above teachings and/or the skill or knowledge of the relevant art. The embodiments described herein above are further intended to explain best modes known by applicant and to enable others skilled in the art to utilize the disclosure in such, or other, embodiments and with the various modifications required by the particular applications or uses thereof. Accordingly, the description is not intended to limit the invention to the form disclosed herein. Also, it is intended to the appended claims be construed to include alternative embodiments. [00272] All publications and patent applications cited in this specification are herein incorporated by reference, and for any and all purposes, as if each individual publication or Attorney Docket No.37759.0543P1 patent application were specifically and individually indicated to be incorporated by reference. In the event of an inconsistency between the present disclosure and any publications or patent application incorporated herein by reference, the present disclosure controls. G. EXAMPLES [00273] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the methods and products claimed herein are made and evaluated, and are intended to be purely exemplary and are not intended to limit the scope of what the inventors regard as their invention. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in °C or is at ambient temperature, and pressure is at or near atmospheric. The Examples are provided herein to illustrate the invention, and should not be construed as limiting the invention in any way. 1. BOLDINE REDUCES MUSCLE ATROPHY AND PROMOTES NEUROMUSCULAR RECOVERY IN A RODENT MODEL OF DELAYED NERVE REPAIR a. M^{ATERIALS AND} M^ETHODS (i) ANIMALS [00274] Male Sprague-Dawley rats (Charles River Laboratories; 300–330 g; aged 6–8 weeks) were used for all experiments. All procedures were approved by the Institutional Animal Care and Use Committees at the University of Pennsylvania and the Michael J. Crescenz Veterans Affairs Medical Center and adhered to the guidelines set forth in the NIH Public Health Service Policy on Humane Care and Use of Laboratory Animals (2015). (ii) BOLDINE ADMINISTRATION [00275] Boldine was procured from (Sigma B3916). Starting 7 days before surgery, rats were trained to eat peanut butter, a previously established oral vehicle for boldine.17 Rats were randomly assigned to the following groups: (A) peanut butter alone (vehicle control; n=12 animals); (B) 50 mg/kg boldine in peanut butter (low dose, n=12); or (C) 100 mg/kg boldine in Attorney Docket No.37759.0543P1 peanut butter (high dose, n=12). A technician fed rats beginning approximately 45 minutes after surgery and once daily thereafter. Animals enrolled in the denervated cohort (described below) received boldine once a day up to the terminal time point (4 weeks) whereas the delayed repair cohort (described below) was given boldine once a day up to 8 weeks post transection (4 weeks post delayed repair). (iii) C^HRONIC R^ODENT C^OMMON P^ERONEAL N^ERVE A^XOTOMY & PROLONGED DENERVATION MODEL [00276] To assess the effect of orally administered boldine on denervated muscle, a previously established rodent chronic axotomy model was adapted (J. C. Burrell, et. al., Bioact Mater 18, 339-353 (2022)). Briefly, animals were anesthetized with isoflurane and the hind leg cleaned with betadine. Meloxicam (2 mg/kg) was administered subcutaneously in the scruff of the neck and bupivacaine (2 mg/kg) was administered subcutaneously along the incision. The gluteal muscle was separated to expose the sciatic nerve exiting the sciatic notch. The common peroneal nerve was sharply transected and a 5 mm segment was removed, and the proximal stump was inserted in a nearby muscle to prevent axon regeneration and neuroma formation. The surgical site was closed with 4-0 absorbable vicryl sutures and skin staples. Animals were recovered and returned to the vivarium until the terminal time point of 4 weeks post nerve transection, with the administration of boldine (or vehicle) occurring daily over that entire time period (n=6 animals for each group: control, low dose boldine, and high dose boldine). See FIG. 1 for experimental timeline. (iv) DELAYED CROSS-SUTURE REPAIR [00277] A separate cohort of animals underwent a neurorrhaphy procedure at 4 weeks after the initial nerve transection (i.e. axotomy). These animals were re-anesthetized and the surgical site was re-exposed. The denervated common peroneal nerve was identified as well as the previously uninjured tibial nerve. Delayed surgical repair was completed by sharply transecting the tibial nerve and refreshing the end of the previously denervated common peroneal nerve by removing approximately 5 mm of fibrotic tissue at the distal stump. Then, a standard end-to-end neurorrhaphy was completed using two 8-0 prolene sutures, securing the proximal tibial nerve with the distal common peroneal nerve. The deep layers and skin were closed, and the area was Attorney Docket No.37759.0543P1 dressed as described above. Animals were recovered and returned to the vivarium until the terminal time point of 6 weeks after the delayed neurorrhaphy procedure (which was 10 weeks after initial axotomy). The administration of boldine (low or high dose) or vehicle (n=6 animals per group) occurred daily until 4 weeks post delayed neurorrhaphy (which was 8 weeks following initial transection). (v) E^{LECTROPHYSIOLOGICAL} A^SSESSMENT [00278] At 2 and 4 weeks post axotomy, and 4 and 6 weeks post delayed neurorrhaphy (corresponding to 8 and 10 weeks post axotomy), evoked muscle response was compared across groups following percutaneous stimulation. Animals were re-anesthetized and a bipolar subdermal stimulating electrode was placed percutaneously superficial to the common peroneal nerve (J. C. Burrell, et. al., Bioact Mater 18, 339-353 (2022)). A monopolar subdermal recording electrode was placed over the muscle belly of the tibialis anterior and the reference electrode placed in its tendon. After determining the initial threshold for evoked muscle recordings, the supramaximal recording was obtained by slowly increasing the current to maximize the amplitude to double the threshold current or until the waveform plateaued, and then averaged over a train of 5 pulses (biphasic; amplitude: 0–5 mA; duration: 0.2 ms; frequency: 1 Hz; 100x gain; 10–10,000 Hz band pass and 60 Hz notch filters; Natus Viking EDX). [00279] At the terminal timepoints of 4 weeks post axotomy and 6 weeks post delayed neurorrhaphy, the surgical site was exposed for direct nerve stimulation and compound muscle action potentials (CMAP) and compound nerve action potentials (CNAP) recordings. To evaluate muscle reinnervation, CMAPs were obtained by stimulating 5 mm proximal or distal to the delayed repair site using a handheld bipolar hook electrode (biphasic; amplitude: 0–4 mA; duration: 0.2 ms; frequency: 1 Hz; 1000x gain; 10–10,000 Hz band pass and 60 Hz notch filters; Natus Viking EDX). Mean peak-to-baseline amplitude were recorded. To assess the electrical conduction across the repair site, CNAPs were recorded by stimulating the proximal stump with a bipolar hook electrode and recording with a bipolar hook electrode (biphasic; amplitude: 0–2 mA; duration: 0.2 ms; frequency: 1 Hz; 1000x gain; 10–10,000 Hz band pass and 60 Hz notch filters; Natus Viking EDX). Mean peak-to-peak amplitude was recorded and conduction velocity was calculated by dividing the distance between the electrodes by the latency between stimulation and evoked response. Attorney Docket No.37759.0543P1 (vi) EUTHANASIA & TISSUE COLLECTION [00280] At the terminal time points, animals were euthanized using carbon dioxide. Nerves were extracted and post-fixed in formalin for 24 hours at 4 °C, and then rinsed in PBS for another 24 hours. Muscles were extracted in paraformaldehyde for 24 hours at 4 °C and then cryoprotected in 20% sucrose. (vii) I^{MMUNOHISTOCHEMISTRY} [00281] For histological assessment, cryoprotected tissue was embedded in optimal cutting media, frozen in dry ice/isopentane, sectioned, and mounted on glass slides for staining. Nerves were sectioned axially at a thickness of 14 μm, 5 mm distal to the injury site. Muscles were sectioned axially at a thickness of 14 μm, starting 100 μm from the proximal muscle belly. [00282] For cross-sectional muscle histology, frozen tissues were washed with PBS three times to remove embedding media, followed by 1 h of blocking and permeabilization in 4% normal horse serum and 0.3% Triton X-100. The primary antibodies were diluted in the previously described blocking solution. Rabbit anti-connexin 43 (1:100, Abcam, ab11370) and rabbit anti-connexin 45 (1:100, Abcam, ab135474) were used to label Cx43 and Cx45, respectively, and anti-synaptophysin (1:500, Abcam, ab32127) to label presynaptic vesicles specifically in the reinnervated cohort. After incubation in primary antibodies overnight at 4 °C, the tissues were washed with PBS three times and incubated for 2 h at room temperature with the corresponding fluorophore-conjugated secondary antibody (1:1000; AlexaFluor, Invitrogen) along with AlexaFluor-488-conjugated phalloidin (1:400, Invitrogen, A12379) to label muscle actin and AlexaFluor-647-conjugated bungarotoxin to label postsynaptic receptors (1:250, Invitrogen, B35450). Hoechst was applied for 10 minutes, then the stained tissues were mounted with Fluoromount G (Southern Biotech, 0100-20) and cover slipped. [00283] For cross-sectional histological analyses of the post-repair distal nerve, frozen sections were washed three times with PBS and blocked for 1 h using the same blocking solution as for muscle histology. The primary antibodies were diluted in 4% of normal horse serum in Optimax (Biogenex), then applied to the sections overnight at 4 °C. Anti-connexin 43 (1:100, Abcam, ab11370) and anti-connexin 45 (1:100, Abcam, ab135474) were used to label Cx43 and Cx45, rabbit anti-S100β (1:500, Invitrogen, PA1-38585) to label Schwann cells, chicken anti- myelin basic protein (Encor, CPCA-MBP; 1:1500) to identify myelin, mouse SMI31 (1:1000, Attorney Docket No.37759.0543P1 Biolegend, 801602) and SMI32 (1:1000, Biolegend, 801701) to label axons, and rabbit anti c-Jun (1:200, Cell Signaling Technologies, 9165L) as an injury marker. After three PBS washes, the sections were incubated in the appropriate fluorophore-conjugated secondary antibody (1:1000; AlexaFluor, Invitrogen) for 1 h at room temperature followed by incubation in Hoechst for 10 min. The staining process ended with Fluoromount G mounting and coverslipping. (viii) D^ATA A^{CQUISITION AND} S^TATISTICAL A^NALYSES [00284] Data was collected by a blinded researcher (unique identifier for all samples) and automatically analyzed when possible (J. C. Burrell, et. al., Bioact Mater 18, 339-353 (2022) and K. V. Panzer, et. al., Front Bioeng Biotechnol 8, 580654 (2020)). Cx43 and Cx45 expression was quantified using the open-source FIJI software, by first measuring the integrated density and the area of the negative control section to calculate its mean integrated density as the background fluorescence measurement. For each sample, the integrated density and area were obtained, then the corrected fluorescence was obtained per Region of Interest (ROI) with the following formula: Corrected Total Fluorescence = Integrated Density – (ROI Area x Background Fluorescence from Negative Control Section). Corrected mean fluorescence was calculated as Corrected Total Fluorescence / ROI Area, averaged across three samples per animal, and compared across groups. [00285] Measurements of muscle fiber area were performed in FIJI software based on phalloidin fluorescence images obtained from a Keyence BZ-X800 microscope. Images were gray-scaled, Gaussian blurred, and converted to binary. The watershed algorithm was applied to separate muscle fibers on the images. The “Analyze Particles” function was then used to obtain the cross-sectional areas of muscle fibers with a size threshold between 200 μm² – 6000 μm². Particles outside this range were assumed to be artifact and were removed prior to analyses. [00286] Axon counts in distal nerves post repair were manually quantified using the count function in NIS elements software from a 40,000 μm² ROI at high magnification in representative z-stacks at maximum projection. The number of non-myelinated axons were counted on SMI31/32 channel and the number of myelinated axons were counted on SMI31/32 + MBP channels. Axon areas and g-ratios were quantified from confocal z-stack maximum projections of two regions of interest (ROIs) per sample and analyzed using FIJI software. For Attorney Docket No.37759.0543P1 each myelinated axon, the inner axon area and the outer (myelinated) axon area were obtained, and the g-ratio was calculated using a modified formula (T. Kaiser, et. al., eNeuro 8, (2021)): ^_{^ − ^^ ^^ ^^ ^^ ^^ = √} ^{^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^} ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ [00287] For the

with Cx43 and C- Jun in distal nerves of the denervated cohort, three representative ROIs were used per animal. The image processing pipeline in NIS elements entails gray-scaling, filtering with a rolling ball background subtraction, fluorescence and size thresholding (0.5 μm–20 μm), watershed segmentation to separate objects, then cleaning smaller particles and filling holes. The function “HAVING” was applied to the Hoechst and S100β layers to obtain the number of S100β+ cells (Schwann cells). The “HAVING” function was also applied to the Hoechst + S100β and Cx43 or C-Jun binary layers to quantify the number of cells co-expressing S100β and Cx43 or C-Jun. [00288] To quantify the total number of acetylcholine receptors (AChR) and percentage of reinnervated neuromuscular junctions, three muscle sections per animal were imaged at low magnification to identify regions of bungarotoxin+ (BGX+) clusters of AchR (10x air objective, 1024 × 1024, Keyence BZ-X800 Fluorescence Microscope). AChR was identified as a region with BGX signal adjacent to edges of muscle fibers as marked by phalloidin. Next, three regions of interest (ROI) were randomly selected and automatically acquired (2 × 2 region, 100x oil objective with a 2x digital zoom, 2048 × 2048, Nikon A1R Confocal Microscope) without the researcher visualizing the synaptophysin channel prior to acquisition. BGX + cells or the total number of AchR receptors were quantified from the low magnification image from each animal. Mature neuromuscular junctions (NMJs) were identified as BGX + cells co-localized with synaptophysin-puncta adjacent to phalloidin + muscle fibers. Mean percent mature NMJs was calculated by dividing the number of mature NMJs by the total number of BGX + receptors, averaged across replicates and by group. [00289] One-way ANOVA was performed on the following outcome metrics followed by post-hoc Tukey’s pairwise test when significant differences were found. For evoked muscle response assessment, mean peak-to-baseline amplitude and area-under-the-curve (AUC) was compared at 2 and 4 weeks following nerve injury, and 4 and 6 weeks post repair. For nerve and muscle electrophysiological function assessment, mean CMAP amplitude and CNAP peak-to- Attorney Docket No.37759.0543P1 peak amplitude and conduction velocity were compared at 6 weeks post repair. For nerve regeneration assessment, mean SMI31 expression and axon size, and myelinated axon count were compared. For Schwann cell morphology assessment, percent of S100β-positive Schwann cells co-labeled with C-Jun were compared. For muscle histology, mean levels of Cx43 and Cx45, mean AchR count, and percent mature NMJ were compared at 6 weeks post delayed nerve repair. To assess muscle fiber diameter, at least 10,000 fibers were measured per group, with approximately the same number per animal, and the cumulative frequency distribution was plotted with the non-linear Gaussian line-of-best-fit. Plots were compared using the two-sample Kolmogorov–Smirnov test to evaluate the agreement between distribution profiles. For all statistical tests, p < 0.05 was required for significance (GraphPad Prism, La Jolla California USA). Mean values presented as mean ± standard deviation unless otherwise noted. b. R^ESULTS (i) T^HE E^{FFECTS OF} B^OLDINE T^{REATMENT ON} C^HRONICALLY DENERVATED MUSCLE [00290] To assess whether boldine administration blocks Cx HC formation and preserves the evoked electrophysiological response, a well-established rodent model of chronic axotomy and prolonged muscle denervation was utilized (S. Y. Fu, et. al., J Neurosci 15, 3876-3885 (1995) and J. C. Burrell, et. al., Bioact Mater 18, 339-353 (2022)). At two weeks following denervation, the amplitude of the evoked muscle response was greater in the high dose boldine cohort compared to control groups (FIG.2; vehicle: 0.41 ± 0.22 mV, low: 0.48 ± 0.21 mV, high: 1.03 ± 0.98). However, no differences in mean amplitude were detected at four weeks post denervation (vehicle: 0.27 ± 0.19 mV, low: 0.43 ± 0.16 mV, high: 0.6 ± 0.36 mV). Similarly, the mean area- under-the-curve (AUC) at 2 weeks was greater in the high dose cohort (vehicle: 0.36 ± 0.22 mVms, low: 0.46 ± 0.22 mVms, high: 1.09 ± 0.9 mVms), and there was no significant differences at 4 weeks (vehicle: 0.24 ± 0.19 mVms, low: 0.43 ± 0.22 mVms, high: 0.63 ± 0.42 mVms). [00291] Referring to FIG.2A and FIG.2B, rats were randomly enrolled into three groups: (a) vehicle; (b) low dose boldine (50 mg/kg); or (c) high dose boldine (100 mg/kg). In this model of prolonged denervation, the common peroneal nerve was transected and the proximal stump was Attorney Docket No.37759.0543P1 sutured to a nearby muscle to prevent nerve regeneration. Animals were fed boldine in peanut butter or peanut butter alone (vehicle) every day starting immediately after nerve transection. Evoked muscle responses were assessed at two and four weeks following transection by placing recording electrodes over the muscle belly of the tibialis anterior (TA) muscle and stimulating electrodes over the denervated common peroneal nerve in close proximity to the TA muscle. FIG.2A shows representative waveforms at 2 weeks post injury are shown. Waveforms were recorded from every animal in this study. At 2 weeks after injury, both the mean amplitude and area-under-the-curve (AUC) measurement of the evoked response were greater in the high and low dose boldine groups compared to the vehicle group (FIG.2B). However, by 4 weeks, there were no statistically significant differences in amplitude or AUC across groups. Without wishing to be bound by theory, these findings suggest that boldine may preserve the evoked muscle response of a denervated muscle for up to 2 weeks post injury. [00292] At 4 weeks post axotomy, the tibialis anterior muscle was isolated and weighed for all groups. While there was a trend towards increased mean muscle weight in the low dose cohort, there were no statistical differences found (FIG.3A-D, wherein at 30 days after axotomy, the distal muscle target was removed and weighed. Atrophy of the ipsilateral muscle was apparent across groups; however, no significant differences in muscle weight were detected). Immunocytochemistry on muscle sections to measure levels of Cx43 and Cx45 was also performed. Here, greater levels of Cx43 and Cx45 in the control group were found as compared to the group receiving low dose boldine, indicating that boldine treatment successfully prevented Cx expression following prolonged denervation (FIG.4A-D). Similarly, the denervated muscle fiber area was measured and found that both boldine groups had a rightward shift compared to the controls, suggesting attenuated fiber atrophy following boldine treatment (FIG.5A-D, vehicle median fiber area: 882.97 µm², low dose: 1062.06 µm², high dose: 924.62 µm²). Indeed, 25% of the fibers measured in the vehicle group had an area less than 587.25 µm², compared to 25% of the fibers in the low and high cohort had an area less than 749.68 µm² and 637.23 µm², respectively. Approximately 25% of the fibers measured in the vehicle group had an area greater than 1000 µm², compared to 35.4% and 26.3% of the fibers in the low and high cohort, respectively. Interestingly, the low dose group was significantly different from the high dose group. While the main goal of this study was to assess the effects of boldine on prolonged muscle denervation, previous studies have shown that Cx43 may play a role in glial cells, such as Attorney Docket No.37759.0543P1 Schwann cells found in the peripheral nerves. Indeed, fewer Schwann cells (labeled with S100B) co-expressing Cx43 at 4 weeks after injury in the high dose cohort were found when compared to the other groups (FIG.6A and FIG.6B; vehicle: 449.7 ± 93.56 cells/mm², 269.1 ± 67.18 cells/mm², 297.4 ± 55.06 cells/mm²). [00293] Referring to FIG.4A-D, immunohistochemistry was performed on denervated TA muscle harvested at 4 weeks following common peroneal nerve transection. Representative images are shown labeling for Cx43 (FIG.4A) and Cx45 (FIG.4B). At 4 weeks post injury, reduced Cx43 (FIG.4C) and Cx45 (FIG.4D) expression was found in the low dose cohort compared to the other cohorts. Without wishing to be bound by theory, these findings suggest that boldine administration may decrease intramuscular Cx43 and Cx45 HC expression following axotomy. [00294] Referring to FIG.5A-D, muscle fibers were automatically segmented from cross- sectional samples stained with phalloidin. A rightward shift observed in both low and high dose groups compared to vehicle, indicating a greater percentage of denervated muscle fibers had a larger fiber area following boldine treatment. Without wishing to be bound by theory, these findings suggest boldine may attenuate muscle fiber atrophy following denervation. Break out histograms from each group are provided. [00295] Referring to FIG.6A and FIG.6B, denervated cross-sectional nerve segments were stained for Schwann cells (S100B) and Connexin 43 (Cx43) were used. Fewer S100+ cells co- expressing Cx43 were found in the boldine cohorts compared to vehicle. Without wishing to be bound by theory, these findings suggest that boldine may reduce connexin hemichannel formation along Schwann cells within the denervated nerve after injury.

Attorney Docket No.37759.0543P1 (ii) THE EFFECTS OF BOLDINE TREATMENT ON N^EUROMUSCULAR R^ECOVERY A^FTER D^ELAYED N^ERVE R^EPAIR [00296] To assess whether boldine administration promotes functional recovery, a delayed neurorrhaphy was performed at 4 weeks post transection in a manner similar to those described in previous studies (S. Y. Fu, et. al., J Neurosci 15, 3876-3885 (1995) and J. C. Burrell, et. al., Bioact Mater 18, 339-353 (2022)). [00297] Evoked muscle responses were measured at 4 and 6 weeks post repair. At 4 weeks post repair, the evoked muscle response was similar between groups; however, by 6 weeks post repair, a greater response was detected in the high dose cohort compared to vehicle (vehicle: 2.36 ± 1.2 mV, low: 2.66 ± 0.95 mV, high: 3.94 ± 1.33 mV) (FIG.7A and FIG.7B). No statistical differences were found for mean AUC at 4 or 6 weeks post delayed repair. At the terminal time point (6 weeks post delayed repair), intraoperative muscle and nerve electrophysiology was assessed. Compound muscle action potentials were comparable across treatment groups (FIG. 8A and FIG.8B). Greater compound nerve action potential magnitudes were found in the low dose group compared to the vehicle control group: (FIG.9A and FIG.9B; 226.9 ± 187.8 µV, low: 640.6 ± 290.4 µV, high: 409 ± 222.7 µV); however, conduction velocities were equivalent between groups (vehicle: 32.54 ± 9.12 m/s, low: 36.43 ± 7.16 m/s, high: 38.96 ± 13.57 m/s). [00298] Referring to FIG.7A and FIG.7B, rats were randomly enrolled into the vehicle, low dose, or high dose groups. The common peroneal nerve was transected and animals were fed peanut butter daily (with or without boldine, depending on group). Representative evoked muscle responses are shown following percutaneous stimulation in FIG.7A. As shown in FIG.7B, no differences in the amplitude of the evoked muscle response were observed at 4 weeks post repair or the mean AUC at 4 or 6 weeks post repair; however, mean amplitude of the evoked muscle response was greater in the high dose cohort than vehicle at 6 weeks post repair. [00299] Referring to FIG.8A and FIG.8B, rats continued to be fed daily until 4 weeks post delayed repair and then the intraoperative electrophysiological assessment was performed at the terminal time point of 6 weeks post delayed repair. Compound muscle action potentials (CMAPs) were assessed by placing a recording electrode over the tibialis anterior muscle and then stimulating either 5 mm proximal or distal to the repair site. Representative CMAP Attorney Docket No.37759.0543P1 waveforms following proximal and distal stimulation are shown on top and bottom, respectively, in FIG.8A. As shown in FIG.8B, no differences in CMAP amplitude were found. [00300] Referring to FIG.9A and FIG.9B, rats continued to be fed daily until 4 weeks post delayed repair and then the intraoperative electrophysiological assessment was performed at the terminal time point of 6 weeks post delayed repair. Compound nerve action potentials were measured by placing a stimulating electrode and recording electrode on the nerve, 5 mm proximal and 5 mm distal to repair site, respectively. FIG.9A shows representative CNAP waveforms are shown, while FIG.9B shows that greater CNAP amplitude was observed in the low cohort compared to the vehicle control and no differences were found in the conduction velocity. [00301] To further contextualize the electrophysiological recovery findings, nerve regeneration and myelination was assessed at 6 weeks post delayed repair (FIG.7A and FIG. 7B). Nerve regeneration was compared by quantifying the axon density distal to the repair site. At 6 weeks post repair, similar regeneration was detected between the vehicle group and low dose boldine group; however, the axon density was reduced in high dose group compared to the vehicle group (vehicle: 577.0 ± 89.80 axons/30,000 µm², low: 363.6 ± 67.63 axons/30,000 µm², high: 300.2 ± 22.71 axons/30,000 µm²). Further analysis revealed greater myelination in the boldine treated groups compared to the vehicle control group (vehicle: 74.85 ± 3.30%, low: 84.9 ± 2.39%, high: 90.5 ± 1.93%), suggesting boldine administration may promote nerve maturation at this early timepoint. [00302] Referring to FIG.10A and FIG.10B, immunohistochemistry was performed on distal common peroneal nerve at 6 weeks following delayed nerve repair. FIG.10A shows representative images are shown labeling regenerating axons (SMI31/32; top) and myelin basic protein (MBP; bottom) for vehicle, low and high dose, respectively. Referring to FIG.10B, fewer regenerated axons were found in the high dose boldine group compared to the vehicle control at 6 weeks post delayed repair; however, greater myelination was observed in the low and high dose boldine experimental groups compared to the vehicle group. Significant differences in g-ratio were also found between the low dose boldine compared to the vehicle group. [00303] Referring to FIG.19, immunohistochemistry was performed on the distal common peroneal nerve stump at 4 weeks post injury. Proximal nerve stumps were secured to the nearby Attorney Docket No.37759.0543P1 muscle to prevent spontaneous axonal regeneration. Representative images are shown of nerve axial cross-sections stained for neurofilament (Scale bar: 20 µm). The vehicle group lacked neurofilament-positive axons. In stark contrast, neurofilament-positive axons were readily observed in the distal nerve stumps of boldine treated rats. Without wishing to be bound by theory, these findings provide further evidence that boldine prevents denervation-induced muscle atrophy by inhibiting catastrophic axonal degeneration. [00304] Detailed muscle morphometric analyses in the reinnervation cohort revealed significant differences between the groups (FIG.11A-D). A leftward shift was observed in the vehicle group compared to both of the boldine groups (vehicle median fiber area: 1078.72 µm², low dose: 1137.03 µm², high dose: 1120.36 µm²). Moreover, 25% of the fibers in the vehicle group were less than 687.21 µm², compared to 25% of the fibers in the low and high cohort had an area less than 795.50 µm² and 778.85 µm², respectively. Approximately 60.3% of fibers were greater than 1000 µm² compared to 66.45% and 65.83% in the low dose and high dose groups, respectively. Additionally, no significant differences in Cx43 and Cx45 expression was found across groups at this time point (FIG.12A-D). Collectively, these findings suggest that boldine administration may enhance muscle fiber recovery from atrophy without disrupting the intrinsic regeneration and maturation mechanisms. [00305] Referring to FIG.11A-D, muscle fibers were automatically segmented from cross- sectional samples stained with phalloidin. Histograms were generated by measuring fibers per animal that were grouped by experimental treatment. A leftward shift was observed in the vehicle group compared to the boldine groups, suggesting diminished recovery from muscle fiber atrophy at 6 weeks post delayed repair in the vehicle-treated animals. Break out histograms from each group are provided. [00306] Referring to FIG.12A-D, immunohistochemistry was performed on the reinnervated TA muscle harvested at 6 weeks following delayed nerve repair. Representative images are shown labeling for Cx43 (FIG.12A) and Cx45 (FIG.12B). At 6 weeks post delayed repair, there was no significant differences in Cx43 or Cx45 expression in the TA muscle (FIG.12C and FIG.12D). [00307] To determine the effect of boldine on neuromuscular junction reinnervation, muscle sections were stained with bungarotoxin (BGX) and synaptophysin (Syn) to label acetylcholine receptors and presynaptic vesicles, respectively (FIG.13A-D). At 6 weeks post neurorraphy, Attorney Docket No.37759.0543P1 significant elevation in acetylcholine receptor expression (BGX) was measured following boldine administration compared to the vehicle controls (vehicle: 51.0 ± 7.04, low: 78.7 ± 4.20, high: 73.4 ± 4.17). However, no statistical differences were detected in the percent co- localization of BGX and Syn (vehicle: 77.8 ± 14.70%, low: 71.3 ± 7.79%, high: 65.9 ± 7.98%). Without wishing to be bound by theory, these findings indicate that boldine administration may preserve the capacity for muscle reinnervation by preventing acetylcholine receptor degradation at this early time point. [00308] Referring to FIG.13A-D, immunohistochemistry was performed on the TA muscle at 6 weeks following delayed nerve repair. FIG.13A shows representative images at low magnification are shown identifying bungarotoxin (BGX)-labeled acetylcholine receptors (AchR) in purple counterstained with phallodin (PHL)-labeled muscle fiber in green. Digital zoom-in insets display BGX expression surrounding PHL-positive muscle fibers. At 6 weeks post delayed repair, greater AchR expression was observed in the low and high dose boldine cohorts compared the vehicle control group (FIG.13B). FIG.13C shows representative images using high magnification, high resolution confocal microscopy revealed reinnervated neuromuscular junctions (NMJs) based on synaptophysin-(Syn) co-localization with BGX+ AchR. As shown in FIG.13D, no statistical differences were detected for reinnervated NMJs. c. DISCUSSION [00309] In the study, the efficacy of daily oral boldine administration was assessed in a rodent model of prolonged denervation and delayed nerve repair. Notably, boldine administration preserved the evoked muscle for 2 weeks after injury and mitigated muscle fiber atrophy up to 4 weeks following axotomy. Without wishing to be bound by theory, these findings suggest that boldine is a compound that might promote functional recovery by preventing the harmful effects of prolonged denervation. Therefore, a delayed nerve repair was next performed to examine the effect of boldine administration on nerve regeneration, muscle reinnervation, and muscle electrophysiological recovery. Notably, greater axon myelination, reinnervated muscle fiber diameter, and acetylcholine receptor expression were measured at 6 weeks post repair (10 weeks total from initial transection injury). However, an important caveat to note is that it is difficult to de-couple the direct and indirect effects of boldine on regeneration. Without wishing to be bound by theory, boldine may prevent muscle atrophy and the healthier muscle promotes axon Attorney Docket No.37759.0543P1 maturation and reinnervation. Collectively, these data suggest that boldine may attenuate muscle atrophy and promote early maturation of regenerated axons. [00310] Seminal research on denervation in skeletal muscles established that when nerves are transected close the muscle, electrophysiological recovery is diminished at an earlier time point than in the case of a more proximal injury. A notable observation was that the longer the nerve stump, the longer the time it can transmit electrical signals to the muscle (C. Eyzaguirre, et. al., Acta Physiol Lat Am 2, 213-227 (1952) and R. Birks, et. al., J Physiol 150, 145-168 (1960)). Cisterna et al. identified acetylcholine as the neuron-derived factor responsible for this phenomenon (B. A. Cisterna, et. al., Nat Commun 11, 1073 (2020)). The nerve stump stores and releases acetylcholine as a protective factor, which activates nicotinic acetylcholine receptors through a post-transcriptional process that suppresses Cx HC expression. Cx43 and Cx45 have been linked to adverse effects on the reinnervation process and blocking them slows the progression of muscle atrophy following denervation (L. A. Cea, et. al., Int J Mol Sci 21, (2020)). The mechanism proposed by Cisterna et al. for myofiber alterations following denervation involves a reduction in acetylcholine release, which leads to the formation of Cx HC and an increase in intracellular Ca²⁺ concentration. This Ca²⁺ influx signals protein degradation in the denervated muscles. Therefore, Cx HC mediated calcium signaling initiates the denervated muscle atrophy process and hinders muscle reinnervation. [00311] Boldine is a special type of Cx HC blocker in that it blocks movement of small molecules through the HC without preventing gap junction communication, which is essential for proper physiological function (R. Hernandez-Salinas, et. al., J Diabetes Res 2013, 593672 (2013), C. Yi, et. al., Glia 65, 1607-1625 (2017) and L. A. Cea, et. al., Biochim Biophys Acta 1862, 1891-1899 (2016)). Additionally, boldine treatment has been reported decrease Cx43 and Cx45 expression in murine myofibers and successfully restored normal innervated myofiber phenotype (L. A. Cea, et. al., Int J Mol Sci 21, (2020)). Moreover, as an acetylcholine esterase inhibitor, boldine prevents the degradation of acetylcholine, increasing its half-life and thus delaying the deleterious impact of denervation on myofibers (A. Kostelnik, M. Pohanka, Biomed Res Int 2018, 9634349 (2018)). The results in the denervation cohort are consistent with previous findings about the role of Cx43/45 and the efficacy of boldine treatment. The control group, which had a higher degree of atrophy as measured by muscle mass and myofiber diameter, expressed higher Cx43/45 immunoreactivity than the group receiving low dose Attorney Docket No.37759.0543P1 boldine. Similar to previous studies (L. A. Cea, et. al., J Membr Biol 245, 423-436 (2012)), denervated muscle fibers upregulate Cx43/45 HC after injury that can be ameliorated with boldine treatment. Notably, a recent study tested boldine administration (50 mg/kg) in mice after spinal cord injury and found treatment did not prevent body weight or muscle weight atrophy (L. A. T. Potter, et. al., bioRxiv, (2022)). In this study, boldine administration was found to preserve the evoked muscle response up to 2 weeks after injury, suggesting boldine may maintain the denervated muscle electrophysiological activity. [00312] Previous work has shown Cx43/45 HC are important for muscle regeneration (L. A. Cea, et. al., J Membr Biol 245, 423-436 (2012) and R. Araya, et. al., J Cell Sci 118, 27-37 (2005)) and detrimental to reinnervation (B. A. Cisterna, et. al., Nat Commun 11, 1073 (2020)). However, the role of Cx43/45 in nerve regeneration remains unclear. Immediately after birth, Cx43 expression upregulates and then gradually decreases (T. Yoshimura, et. al., J Neurochem 67, 1252-1258 (1996)); however, adult nerves express Cx43 in the perineurium (K. J. Chandross, et. al., Mol Cell Neurosci 7, 501-518 (1996)) and localized in Schwann cells body (T. Yoshimura, M. Satake, T. Kobayashi, Connexin43 is another gap junction protein in the peripheral nervous system. J Neurochem 67, 1252-1258 (1996)). Intraneural Cx43 expression has also been reported to upregulate after injury and downregulate to baseline during regeneration, and may be important the myelination process (K. J. Chandross, et. al., Mol Cell Neurosci 7, 501-518 (1996)). Therefore, boldine administration was stopped at 4 weeks after delayed repair, which was calculated to be the approximate minimal time point for early reinnervation. At 6 weeks post delayed repair (2 weeks after boldine administration ended), intramuscular Cx43/45 HC expression was similar across groups; however, reinnervated muscle fiber diameter was greater in the boldine cohort. These results suggest that boldine can be used to prevent the harmful consequences of denervation without causing permanent damage to the intrinsic processes involved in muscle regeneration. [00313] Although previous studies have shown boldine decreases Cx43/45 expression in denervated muscle, this is the first study to report boldine administration decreased intraneural Cx43 expression after nerve injury. Moreover, these findings suggest the effect of boldine treatment on Cx43/45 may be reversible after terminating administration, allowing for normal maturation and myelination processes. Notably, although boldine treatment decreased Cx43 expression surrounding Schwann cells after nerve injury, additional experiments are necessary to Attorney Docket No.37759.0543P1 elucidate any changes in pro-regenerative Schwann cell mechanisms. For instance, acetylcholinesterase has been reported to impede axonal elongation and then promote elongation on inhibition, and boldine may have similar paradoxical effects (J. E. Keymer, et. al., European Journal of Neuroscience 11, 1049-1057 (1999)). Overall, boldine treatment does not appear to impact regeneration at the early time points investigated in this study; however, future efficacy studies may be necessary to further evaluate the chronic effects on functional recovery. [00314] After PNI, surgeons often utilize a wait-and-see approach prior to surgical intervention in hope of spontaneous recovery. While some patients may recover, more severe cases requiring delayed surgical reconstruction have a diminished likelihood for restoration. This study demonstrates that boldine administration may be a potential pharmaceutical intervention that promotes functional recovery after delayed nerve repair. Additionally, pharmacological treatment of muscle denervation may be a useful adjunct for advanced tissue engineering strategies that replace damaged nervous structures (J. C. Burrell, et. al., Bioact Mater 18, 339- 353 (2022), K. S. Katiyar, et. al., Tissue Eng Part A 27, 1305-1320 (2021), K. S. Katiyar, et. al., Front Bioeng Biotechnol 8, 492 (2020), R. B. Shultz, et. al., J Tissue Eng 12, 20417314211032488 (2021), D. H. Smith, et. al., Sci Adv 8, eabm3291 (2022), Q. Zhang, et. al., Stem Cell Res Ther 13, 263 (2022), Q. Zhang, et. al., NPJ Regen Med 6, 59 (2021), Q. Zhang, et. al., Sci Rep 8, 6634 (2018), and Q. Zhang, et. al., Mol Neurobiol 55, 6965-6983 (2018). In summary, these findings demonstrate promising effects of boldine administration on preservation of muscle function following nerve injury as well as on enhancing neuromuscular functional recovery after delayed nerve repair. 2. E^{FFECTS OF} M^USCLE R^ESTRICTED C^X43/45 ^KNOCKOUTS [00315] A series of experiments was designed to understand the functional significance of the upregulation of Cx43/45 in muscle fibers of rats after spinal cord transection. Transgenic mice were generated in which expression of Cx43 and Cx45 in skeletal muscle was ablated. These mice were generated by crossing mice in which a portion of the myoD gene was replaced with a modified Cre such that Cre would be expressed in all tissues in which myoD is expressed. These mice were crossed with mice in which loxP sites were introduced into the genes for Cx43 and Cx45 such that expression of Cre would result in expression of an inactive version of each of Attorney Docket No.37759.0543P1 these Cx. This line, called (myoD-Cre/wt)/Cx43(f/f)/Cx45(f/f), and its genotype control called Cx43(f/f)/C45(f/f) were used in the experiments described below. a. E^{FFECTS OF} C^X43/45 ^CKO ^ON M^USCLE M^{ASS AND} S^TRENGTH A^FTER SPINAL CORD TRANSECTION. [00316] A spinal cord transection was performed at the 9^th thoracic vertebra as previously described (Graham, Z.A., et al., Neurotrauma Reports, 20201(1) 17-31). Mice were provided post-operative care as described (Graham, Z.A., et al., Neurotrauma Reports, 20201(1) 17-31). Electrophysiological testing of extensor digitorum longus (EDL) muscle was performed using an Aurora Scientific ex vivo physiological testing apparatus according to the manufacturer’s recommended procedures. [00317] The double Cx43/45 cKO slightly though significantly increased wet weights of gastrocnemius muscles in male mice but did not alter wet muscle weights in females (data not shown). These data argue against a robust effect of the double Cx43/45 cKO on muscle atrophy after spinal cord transection. Reasons for the observed gender discordance are unknown but may related to recently observed links between actions of boldine on androgen signaling pathways (Potter, L., et al., bioRxiv, 2022: p.2022.08.17.503230). The testing of muscle contractile performance revealed a significant increase in strength of EDL muscle from Cx43/45 double cKO mice as compared to genotype controls (FIG.14). [00318] Referring to FIG.14, force-frequency measurements were performed at 14 days after complete spinal cord transection at T9 using EDL muscle by ex vivo physiological testing. Data were normalized using mixed-model 2-way ANOVA which revealed a significant main effect for genotype and frequency. Data are mean values ± SEM for 7-8 mice per group. b. CHANGES IN THE FUNCTIONAL AND METABOLIC OUTCOMES AFTER A MODERATE SEVERITY CONTUSION SCI. [00319] (myoD-Cre/wt)/Cx43(f/f)/Cx45(f/f) mice underwent a 65 kdyne contusion injury of the spinal cord using an Infinite Horizons impactor with the tip centered over the middle of the 9^th thoracic vertebra. Controls (Cx43(f/f)/Cx45(f/f) mice) underwent a laminectomy only. Surgeries and post-operative care were performed as described in recent publications (Toro, C.A., et al., bioRxiv, 2023: p.2023.02.15.528337 and Toro, C.A., et al., Front Cell Neurosci, Attorney Docket No.37759.0543P1 2021.15: p.626192). Physical function of mice was followed using the Basso Mouse Scale (BMS) (Basso, D.M., et al., J Neurotrauma, 2006.23(5): p.635-59) to evaluate hindlimb function and the horizontal ladder rung walk test (LRWT) to assess fine motor skills (Cummings, B.J., et al., Behav Brain Res, 2007.177(2): p.232-41). [00320] The double knockout improved physical function after SCI, particularly in males. Data for tests of physical function were analyzed using 2-way mixed model ANOVA. For both males and females, a highly significant main effect was detected for genotype for results of BMS and LRWT indicating that mice with the double Cx43/45 cKO demonstrated better function. [00321] A double Cx43/45 cKO mitigated changes in metabolic function after spinal cord contusion. Altered levels of metabolic intermediates were observed, including lactate and pyruvate (Graham, Z.A., et al., J Neurotrauma, 2019.36(18): p.2722-2731) and noted that boldine, a CxHC blocker (Yi, C., et al., Glia, 2017.65(10): p.1607-1625), normalizes metabolomic and lipidomic signatures in skeletal muscle of mice after spinal cord transection (Potter, L., et al., bioRxiv, 2022: p.2022.08.17.503230). To understand if these tissue level biochemical changes were linked to whole body metabolic phenotypes, metabolic cage studies were performed on sub-groups of mice used in the experiment shown in FIG.15A and FIG. 15B. Analysis of these data by two-way mixed-model ANOVA showed a significant main effect for genotype indicating that the double Cx43/45 knockout prevented the decline in oxygen consumption (FIG.16A) and caloric expenditure (FIG.16B) that occurred after SCI without any evident change in respiratory quotient, in-cage activity or food intake (data not shown). [00322] Referring to FIG.15A and FIG.15B, physical function of mice with double knockouts of Cx43/45 in muscle cells and genotype controls after 65 kdyne contusion SCI or laminectomy is summarized for males (2A) and females (2B). Violin plots show individual data points, the median value (dotted line) and the upper and lower quartiles (solid line). [00323] Referring to FIG.16A and FIG.16B, the effect of a Cx43/45 double cKO on metabolic cage parameters. A subgroup of mice from the experiment for which data are shown in Figure 2 underwent assessment of metabolic parameters in a Sable Systems Promethion metabolic cage system. Data are average values for a 24 hour period. Violin plots show individual data points, the median value (dotted line) and the upper and lower quartiles (solid line). Attorney Docket No.37759.0543P1 c. EFFECTS OF BOLDINE ON SERUM LIPIDOMICS AND METABOLOMICS P^{ROFILES IN} M^{ICE WITH} S^PINAL C^ORD T^RANSECTION. [00324] Unbiased liquid chromatography/mass-spectrometry-based methods was utilized for profiling lipids and metabolites to evaluate these “omics” profiles in serum collected at 7 days from mice used in recent investigations of effects of boldine on perturbations on “omics” signatures in gastrocnemius muscle, one of the muscles of the calf that is paralyzed by the spinal cord transection performed. [00325] It was found that boldine normalized levels of phosphatidylinositols present in serum of mice that was collected at 7 days after a spinal cord transection (FIG.17A-D). Among the lipid altered in serum by spinal cord transect were four phosphatidylinositols, lipids which are vital for intracellular signaling. Levels of each of these were increased in serum of spinal cord transected mice treated with vehicle whereas levels were normalized in mice treated with boldine. Without wishing to be bound by theory, the biological significance of the finding remains unknown, but the data do suggest that boldine might normalize intracellular signaling in the region of the injury. Whether elevated levels of these lipids in serum reflects greater cellular injury and consequent release is unknown. [00326] It was also found that boldine altered serum levels of agonists at serotonin receptors; a heat map showed relative levels of selected metabolites in serum from spinal cord transected mice treated with vehicle (SCIv) or boldine (SCIb) (FIG.18). While the metabolomics analysis of serum was limited because none of the metabolites detected were significantly altered when correcting for false discovery rates (a statistical method designed to reduce numbers of false- positive findings when tens, hundreds or thousands of comparisons are made in a single experiment), exploratory examination of the data using raw p values revealed a significant number of metabolites that were different when comparing control, vehicle-treated and boldine treated SCI animals. Extending this approach to metabolites present in different levels in serum when comparing SCI mice treated with vehicle or boldine revealed several metabolites that activate serotonergic receptors, specifically serotonin and 5-methoxytryptamine. Again, understanding the biological significance of these findings requires further experimentation, but given that serotonin is released by descending fibers arising in the brain that synapse with neurons serving multiple different functions in the spinal cord the results are provocative. Attorney Docket No.37759.0543P1 d. DISCUSSION [00327] The data show that de-novo expression of Cx43/45 in skeletal muscle has previously unknown deleterious effects on muscle contractility and metabolic function. 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Cullen, Tissue-engineered grafts exploit axon-facilitated axon regeneration and pathway protection to enable recovery after 5-cm nerve defects in pigs. Sci Adv 8, eabm3291 (2022). [00365] Q. Zhang, J. C. Burrell, J. Zeng, F. I. Motiwala, S. Shi, D. K. Cullen, A. D. Le, Implantation of a nerve protector embedded with human GMSC-derived Schwann-like cells accelerates regeneration of crush-injured rat sciatic nerves. Stem Cell Res Ther 13, 263 (2022). [00366] Q. Zhang, P. Nguyen, J. C. Burrell, J. Zeng, S. Shi, R. M. Shanti, G. Kulischak, D. K. Cullen, A. D. Le, Harnessing 3D collagen hydrogel-directed conversion of human GMSCs into SCP-like cells to generate functionalized nerve conduits. NPJ Regen Med 6, 59 (2021). [00367] Q. Zhang, P. D. Nguyen, S. Shi, J. C. Burrell, D. K. Cullen, A. D. Le, 3D bio-printed scaffold-free nerve constructs with human gingiva-derived mesenchymal stem cells promote rat facial nerve regeneration. Sci Rep 8, 6634 (2018). [00368] Q. Zhang, P. D. Nguyen, S. Shi, J. C. Burrell, Q. Xu, K. D. Cullen, A. D. Le, Neural Crest Stem-Like Cells Non-genetically Induced from Human Gingiva-Derived Mesenchymal Stem Cells Promote Facial Nerve Regeneration in Rats. Mol Neurobiol 55, 6965-6983 (2018). [00369] Chen, M.J., et al., Astrocytic CX43 hemichannels and gap junctions play a crucial role in development of chronic neuropathic pain following spinal cord injury. Glia, 2012.60(11): p.1660-70. [00370] Sáez, J.C., et al., Regulation of pannexin and connexin channels and their functional role in skeletal muscles. Cell Mol Life Sci, 2015.72(15): p.2929-35. [00371] Toro, C.A., et al., Boldine modulates glial transcription and functional recovery in a murine model of contusion spinal cord injury. bioRxiv, 2023: p.2023.02.15.528337. [00372] Graham, Z.A., et al., Effects of a High-Fat Diet on Tissue Mass, Bone, and Glucose Tolerance after Chronic Complete Spinal Cord Transection in Male Mice. Neurotrauma Reports, 2020.1(1): p.17-31. [00373] Toro, C.A., et al., The Human ApoE4 Variant Reduces Functional Recovery and Neuronal Sprouting After Incomplete Spinal Cord Injury in Male Mice. Front Cell Neurosci, 2021.15: p.626192. [00374] Basso, D.M., et al., Basso Mouse Scale for locomotion detects differences in recovery after spinal cord injury in five common mouse strains. J Neurotrauma, 2006.23(5): p.635-59. Attorney Docket No.37759.0543P1 [00375] Cummings, B.J., et al., Adaptation of a ladder beam walking task to assess locomotor recovery in mice following spinal cord injury. Behav Brain Res, 2007.177(2): p.232-41. [00376] Graham, Z.A., et al., Key Glycolytic Metabolites in Paralyzed Skeletal Muscle Are Altered Seven Days after Spinal Cord Injury in Mice. J Neurotrauma, 2019.36(18): p.2722- 2731. [00377] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope or spirit of this disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit being indicated by the following claims.

Claims

Attorney Docket No.37759.0543P1 CLAIMS What is claimed is: 1. A method of treating or preventing a peripheral nerve injury in a subject in need thereof, the method comprising administering to the subject an effective amount of a compound having a structure represented by a formula: , 1

wherein R is selected from wherein R² is selected from hydrogen, halogen, –CN, –NH₂, –OH, –NO₂, C1-C4 alkyl, C2- C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1- C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl; wherein each of R³ and R⁴ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl, or wherein R³ and R⁴ join together to form a ring having 5-7 atoms; wherein each of R⁵ and R⁶ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl, or wherein R⁵ and R⁶ join together to form a ring having 5-7 atoms; and wherein R⁷ is selected from hydrogen, halogen, –CN, –NH2, –OH, –NO2, C1-C4 alkyl, C2- C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1- C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl; or a pharmaceutically acceptable salt thereof. Attorney Docket No.37759.0543P1 2. The method of claim 1, wherein R¹ is C1-C4 alkyl. 3. The method of claim 1, wherein R¹ is methyl. 4. The method of any one of claims 1 to 4, wherein each of R² and R⁷ is hydrogen. 5. The method of any one of claims 1 to 4, wherein each of R³ and R⁴ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1- C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl. 6. The method of any one of claims 1 to 5, wherein R³ is selected from hydrogen and C1-C4 alkyl. 7. The method of any one of claims 1 to 6, wherein R³ is hydrogen. 8. The method of any one of claims 1 to 8, wherein R⁴ is selected from hydrogen and C1-C4 alkyl. 9. The method of any one of claims 1 to 8, wherein R⁴ is C1-C4 alkyl. 10. The method of any one of claims 1 to 9, wherein R⁴ is methyl. 11. The method of any one of claims 1 to 10, wherein each of R⁵ and R⁶ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1- C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl. 12. The method of any one of claims 1 to 11, wherein R⁵ is selected from hydrogen and C1- C4 alkyl. 13. The method of any one of claims 1 to 12, wherein R⁵ is C1-C4 alkyl. 14. The method of any one of claims 1 to 13, wherein R⁵ is methyl. 15. The method of any one of claims 1 to 14, wherein R⁶ is selected from hydrogen and C1- C4 alkyl. Attorney Docket No.37759.0543P1 16. The method of any one of claims 1 to 15, wherein R⁶ is hydrogen. 17. The method of claim 1, wherein each of R¹, R⁴, and R⁵ is independently selected from hydrogen, methyl, ethyl, and propyl; wherein each of R² and R⁷ is independently selected from hydrogen and halogen; and wherein each of R³ and R⁶ is hydrogen. 18. The method of claim 1, wherein each of R¹, R⁴, and R⁵ is methyl; wherein each of R² and R⁷ is independently selected from hydrogen and halogen; and wherein each of R³ and R⁶ is hydrogen. 19. The method of claim 1, wherein each of R¹, R⁴, and R⁵ is independently selected from hydrogen, methyl, ethyl, and propyl; and wherein each of R², R³, R⁶, and R⁷ is hydrogen. 20. The method of claim 1, wherein the compound is: ,

or a pharmaceutically acceptable salt thereof. 21. The method of claim 1, wherein the compound is: ,

or a pharmaceutically acceptable salt thereof. 22. The method of claim 1, wherein the compound is: Attorney Docket No.37759.0543P1 OH OR⁴ , or a pharmaceutically acceptable

23. The method of claim 1, wherein the compound is: OH OR⁴ ,

or a pharmaceutically acceptable 24. The method of claim 1, wherein the compound is: ,

or a pharmaceutically acceptable salt thereof. 25. The method of claim 1, wherein the compound is: , Attorney Docket No.37759.0543P1 or a pharmaceutically acceptable salt thereof. 26. The method of any one of claims 1 to 25, wherein the effective amount is a therapeutically effective amount. 27. The method of claim 26, wherein the peripheral nerve injury is due to an iatrogenic injury. 28. The method of claim 27, wherein administering occurs from about 10 minutes to about 72 hours after the iaotrogenic injury. 29. The method of claim 28, wherein the peripheral nerve injury is due to a non-iatrogenic injury. 30. The method of claim 29, wherein administering occurs from about 30 minutes to about 1 year after the non-iaotrogenic injury. 31. The method of any one of claims 1 to 25, wherein the effective amount is a prophylactically effective amount. 32. The method of claim 31, wherein the subject does not currently have a peripheral nerve injury. 33. The method of claim 31, wherein the subject is at risk for receiving a peripheral nerve injury. 34. The method of claim 33, wherein the subject is undergoing a medical procedure for which a peripheral nerve injury is a possible side effect within no more than about 72 hours after the administering step. 35. The method of claim 34, wherein the medical procedure is a tumor resection. 36. The method of any one of claims 1 to 35, wherein the compound is administered to the subject via oral, parenteral, or intramuscular administration. Attorney Docket No.37759.0543P1 37. The method of any one of claims 1 to 35, wherein the compound is administered to the subject via local administration. 38. The method of any one of claims 1 to 37, wherein the subject is a mammal. 39. The method of any one of claims 1 to 37, wherein the subject is a human. 40. The method of any one of claims 1 to 39, wherein the subject has been diagnosed with a need for treatment or prevention of the peripheral nerve injury prior to the administering step. 41. The method of any one of claims 1 to 39, further comprising the step of identifying a subject in need of treatment or prevention of the peripheral nerve injury. 42. The method of any one of claims 1 to 41, wherein treating promotes neuromuscular recovery. 43. The method of any one of claims 1 to 41, wherein treating promotes improved sensation. 44. The method of any one of claims 1 to 41, wherein treating decreases atrophied muscle volume. 45. A method of treating or preventing denervation-induced muscular atrophy in a subject in need thereof, the method comprising administering to the subject an effective amount of a compound having a structure represented by a formula: ,

wherein R¹ is selected from hydrogen and C1-C4 alkyl; wherein R² is selected from hydrogen, halogen, –CN, –NH2, –OH, –NO2, C1-C4 alkyl, C2- C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1- C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl; Attorney Docket No.37759.0543P1 wherein each of R³ and R⁴ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl, or wherein R³ and R⁴ join together to form a ring having 5-7 atoms; wherein each of R⁵ and R⁶ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl, or wherein R⁵ and R⁶ join together to form a ring having 5-7 atoms; and wherein R⁷ is selected from hydrogen, halogen, –CN, –NH2, –OH, –NO2, C1-C4 alkyl, C2- C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1-C4 hydroxyalkyl, C1-C4 haloalkoxy, C1- C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl, or a pharmaceutically acceptable salt thereof. 46. The method of claim 45, wherein R¹ is C1-C4 alkyl. 47. The method of claim 45 or claim 46, wherein R¹ is methyl. 48. The method of any one of claims 45 to 47, wherein each of R² and R⁷ is hydrogen. 49. The method of any one of claims 45 to 48, wherein each of R³ and R⁴ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1- C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl. 50. The method of any one of claims 45 to 49, wherein R³ is selected from hydrogen and C1- C4 alkyl. 51. The method of any one of claims 45 to 50, wherein R³ is hydrogen. 52. The method of any one of claims 45 to 51, wherein R⁴ is selected from hydrogen and C1- C4 alkyl. 53. The method of any one of claims 45 to 52, wherein R⁴ is C1-C4 alkyl. Attorney Docket No.37759.0543P1 54. The method of any one of claims 45 to 53, wherein R⁴ is methyl. 55. The method of any one of claims 45 to 54, wherein each of R⁵ and R⁶ is independently selected from hydrogen, C1-C4 alkyl, C2-C4 alkenyl, C1-C4 haloalkyl, C1-C4 cyanoalkyl, C1- C4 hydroxyalkyl, C1-C4 haloalkoxy, C1-C4 alkoxy, C1-C4 alkylamino, (C1-C4)(C1-C4) dialkylamino, and C1-C4 aminoalkyl. 56. The method of any one of claims 45 to 55, wherein R⁵ is selected from hydrogen and C1- C4 alkyl. 57. The method of any one of claims 45 to 56, wherein R⁵ is C1-C4 alkyl. 58. The method of any one of claims 45 to 57, wherein R⁵ is methyl. 59. The method of any one of claims 45 to 58, wherein R⁶ is selected from hydrogen and C1- C4 alkyl. 60. The method of any one of claims 45 to 59, wherein R⁶ is hydrogen. 61. The method of claim 45, wherein each of R¹, R⁴, and R⁵ is independently selected from hydrogen, methyl, ethyl, and propyl; wherein each of R² and R⁷ is independently selected from hydrogen and halogen; and wherein each of R³ and R⁶ is hydrogen. 62. The method of claim 45, wherein each of R¹, R⁴, and R⁵ is methyl; wherein each of R² and R⁷ is independently selected from hydrogen and halogen; and wherein each of R³ and R⁶ is hydrogen. 63. The method of claim 45, wherein each of R¹, R⁴, and R⁵ is independently selected from hydrogen, methyl, ethyl, and propyl; and wherein each of R², R³, R⁶, and R⁷ is hydrogen. 64. The method of claim 45, wherein the compound is: Attorney Docket No.37759.0543P1 , or a pharmaceutically acceptable

65. The method of claim 45, wherein the compound is: ,

or a pharmaceutically acceptable 66. The method of claim 45, wherein the compound is: OH ,

or a pharmaceutically acceptable salt thereof. 67. The method of claim 45, wherein the compound is: Attorney Docket No.37759.0543P1 OH OR⁴ , or a pharmaceutically acceptable

68. The method of claim 45, wherein the compound is: ,

or a pharmaceutically acceptable 69. The method of claim 45, wherein the compound is: ,

or a pharmaceutically acceptable salt thereof. 70. The method of any one of claims 45 to 69, wherein the denervation-induced muscular atrophy is due to trauma, an autoimmune disorder, or a viral infection. 71. The method of any one of claims 45 to 69, wherein the denervation-induced muscular atrophy is due to nerve injury or nerve transection. Attorney Docket No.37759.0543P1 72. The method of any one of claims 45 to 69, wherein the denervation-induced muscular atrophy is due to diabetic neuropathy, degenerative disc disease, alcoholic neuropathy, pernicious anemia, amyotrophic lateral sclerosis (ALS), Guillain-Barré syndrome, spinal muscular atrophy, or Charcot-Marie-Tooth disease. 73. The method of any one of claims 45 to 69, wherein the effective amount is a therapeutically effective amount. 74. The method of claim 71, wherein the denervation-induced muscular atrophy is due to an iatrogenic injury. 75. The method of claim 72, wherein administering occurs from about 10 minutes to about 72 hours after the iaotrogenic injury. 76. The method of claim 71, wherein the denervation-induced muscular atrophy is due to a non-iatrogenic injury. 77. The method of claim 72, wherein administering occurs from about 30 minutes to about 1 year after the non-iaotrogenic injury. 78. The method of any one of claims 45 to 69, wherein the effective amount is a prophylactically effective amount. 79. The method of claim 76, wherein the subject is not currently experiencing denervation- induced muscular atrophy. 80. The method of claim 76, wherein the subject is at risk for developing denervation- induced muscular atrophy. 81. The method of claim 80, wherein the subject is undergoing a medical procedure for which a peripheral nerve injury is a possible side effect within no more than about 72 hours after the administering step. 82. The method of claim 81, wherein the medical procedure is a tumor resection. Attorney Docket No.37759.0543P1 83. The method of any one of claims 45 to 69, wherein the compound is administered to the subject via oral, parenteral, or intramuscular administration. 84. The method of any one of claims 45 to 69, wherein the compound is administered to the subject via local administration. 85. The method of any one of claims 45 to 69, wherein the subject is a mammal. 86. The method of any one of claims 45 to 69, wherein the subject is a human. 87. The method of any one of claims 45 to 69, wherein the subject has been diagnosed with a need for treatment or prevention of the denervation-induced muscular atrophy prior to the administering step. 88. The method of any one of claims 45 to 69, further comprising the step of identifying a subject in need of treatment or prevention of the denervation-induced muscular atrophy.