RU2851203C2 - Tetracyclic heterocyclic compounds useful as hiv integrase inhibitors - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to a compound having the structure specified below, or a pharmaceutically acceptable salt thereof, which has the property of inhibiting HIV integrase and may be used for the treatment or prevention of HIV infection or for the treatment, prevention or retardation of the onset or progression of AIDS in a subject in need thereof. The invention also relates to a pharmaceutical composition comprising said compound.

EFFECT: treatment of HIV infection or treatment, prevention or slowing of the onset or progression of AIDS in a subject in need thereof and its use for inhibiting HIV integrase.

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Description

FIELD TO WHICH THE INVENTION RELATES

The present invention relates to tetracyclic heterocyclic compounds, compositions comprising at least one tetracyclic heterocyclic compound, and methods of using the tetracyclic heterocyclic compounds to treat or prevent HIV infection in a subject.

PREREQUISITES FOR THE CREATION OF THE INVENTION

The retrovirus called human immunodeficiency virus (HIV), and specifically the strains known as HIV virus type 1 (HIV-1) and virus type 2 (HIV-2), is the etiologic agent of a complex disease that includes progressive destruction of the immune system (acquired immunodeficiency syndrome; AIDS) and degeneration of the central and peripheral nervous system. A common feature of retroviral replication is the insertion of proviral DNA into the host cell genome via virally encoded integrase, a necessary step for HIV replication in human T lymphoid and monocytoid cells. Integration is thought to be mediated by integrase in three steps: assembly of a stable nucleoprotein complex with viral DNA sequences; The cleavage of two nucleotides from the 3' ends of the linear proviral DNA and the covalent attachment of the recessed 3'-OH ends of the proviral DNA to a staggered nickle made at the host target site. The fourth stage of the process, reparative synthesis of the resulting gap, can be performed by cellular enzymes.

Nucleotide sequencing of HIV reveals the presence of the pol gene in a single open reading frame [Ratner, L. et al., Nature, 313, 277 (1985)]. Amino acid sequence homology indicates that the pol sequence encodes HIV reverse transcriptase, integrase, and protease [Toh, H. et al., EMBO J. 4, 1267 (1985); Power, M.D. et al., Science, 231, 1567 (1986); Pearl, L.H. et al., Nature, 329, 351 (1987)]. All three enzymes have been shown to be essential for HIV replication.

Certain antiviral compounds that act as inhibitors of HIV replication are known to be effective in the treatment of AIDS and related diseases, including reverse transcriptase inhibitors such as azidothymidine (AZT) and efavirenz, and protease inhibitors such as indinavir and nelfinavir. The compounds of the present invention are inhibitors of HIV integrase and inhibitors of HIV replication.

ESSENCE OF THE INVENTION

In one aspect, the present invention provides compounds of formula (I):

(I)

or their pharmaceutically acceptable salts,

Where:

R ¹ is CHR ² -OC(O)-YR ³ , C(O)-C ₁ -C ₁₀ alkyl, CHR ² -OP(O)(OH) ₂ or

;

Y represents a bond or -O-;

R ² is hydrogen or C ₁ -C ₆ alkyl;

R ³ is selected from the group consisting of C ₁ -C ₆ alkyl, (CH ₂ ) _x -OC ₁ -C ₆ alkyl and (CH ₂ ) _x -NR ⁴ R ⁵ , wherein said C ₁ -C ₆ alkyl group may be optionally substituted with one to three groups independently selected from the group consisting of halogen, hydroxy, methoxy and ethoxy;

R ⁴ is hydrogen or C ₁ -C ₆ alkyl;

R ⁵ is hydrogen or C ₁ -C ₆ alkyl;

x is an integer between one and four.

Compounds of formula (I) (also referred to in this application as "tetracyclic heterocyclic compounds") and their pharmaceutically acceptable salts or prodrugs may be useful, for example, for inhibiting HIV viral replication or replicon activity, or for treating or preventing HIV infection in a subject. Without being limited to any particular theory, it is believed that tetracyclic heterocyclic compounds inhibit HIV viral replication by inhibiting HIV integrase.

Accordingly, the present invention provides methods for treating or preventing HIV infection in a subject, comprising administering to the subject an effective amount of at least one tetracyclic heterocyclic compound of Formula I or pharmaceutically acceptable salts thereof.

The details of the invention are set forth below in the accompanying detailed description.

Although any methods and materials similar to those described herein can be used in the practice or testing of the present invention, illustrative methods and materials will now be described. Other embodiments, aspects, and features of the present invention are either described below or will be apparent from the following description, examples, and appended claims.

DETAILED DESCRIPTION OF THE INVENTION

The present invention includes tetracyclic heterocyclic compounds, compositions comprising at least one tetracyclic heterocyclic compound, and methods of using the tetracyclic heterocyclic compounds to treat or prevent HIV infection in a subject.

Definitions and abbreviations

The terms used in this application have their ordinary meaning, and the meaning of such terms is independent in each case. Notwithstanding this and except where otherwise indicated, the following definitions apply throughout the specification and claims. Chemical names, common names, and chemical structures may be used interchangeably to describe the same structure. These definitions apply regardless of whether the term is used alone or in combination with other terms, unless otherwise indicated. Therefore, the definition "alkyl" applies to "alkyl" as well as to the "alkyl" portions of "hydroxyalkyl," "haloalkyl," "-O-alkyl," etc.

The following terms used in this section and throughout this disclosure, unless otherwise specified, shall be understood to have the following meanings:

A "subject" is a human or a non-human mammal. In one embodiment, the subject is a human. In another embodiment, the subject is a primate. In another embodiment, the subject is a monkey. In another embodiment, the subject is a chimpanzee. In yet another embodiment, the subject is a rhesus macaque.

The term "effective amount" as used herein refers to the amount of a tetracyclic heterocyclic compound and/or an additional therapeutic agent, or a composition thereof, that effectively inhibits HIV replication and produces the desired therapeutic, ameliorating, inhibitory, or prophylactic effect when administered to a subject suffering from HIV infection or AIDS. In the combination therapy of the present invention, the effective amount may refer to each individual agent or to the combination as a whole, wherein the amounts of all agents administered together are effective, but wherein the component of the combination alone may not be present in an effective amount.

The term "treatment" when used in this application in relation to the HIV viral infection or AIDS includes inhibiting the severity of the HIV infection or AIDS, i.e. suppressing or reducing the progression of the HIV infection or AIDS or their clinical symptoms; or alleviating the course of the HIV infection or AIDS, i.e. inducing regression of the severity of the HIV infection or AIDS or their clinical symptoms.

The terms “prevention” or “prophylaxis,” when used in this application in relation to HIV viral infection or AIDS, refer to reducing the likelihood or severity of HIV infection or AIDS.

The term "alkyl" as used herein refers to an aliphatic hydrocarbon group having one of the hydrogen atoms replaced by a bond. An alkyl group may be straight or branched and contain from about 1 to about 20 carbon atoms. In one embodiment, an alkyl group contains from about 1 to about 12 carbon atoms. In various embodiments, an alkyl group contains from 1 to 6 carbon atoms (C ₁ -C ₆ alkyl) or from about 1 to about 10 carbon atoms (C ₁ -C ₁₀ alkyl). Non-limiting examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, isopentyl, n-hexyl, isohexyl, and neohexyl. In one embodiment, the alkyl group is straight. In another embodiment, the alkyl group is branched. Unless otherwise noted, the alkyl group is unsubstituted.

The term “halogen” as used in this application means -F, -Cl, -Br or -I.

The term "substituted" means that one or more hydrogen atoms are replaced at the designated atom by a substituent selected from the indicated group, provided that the normal valence of the designated atom under the existing conditions is not exceeded, and that the substitution results in a stable compound. Combinations of substituents and/or variables are permissible only if such combinations result in stable compounds. By "stable compound" or "stable structure" is meant a compound that is sufficiently robust to withstand isolation to an acceptable degree of purity from a reaction mixture and formulation into an effective therapeutic agent.

The term "in substantially purified form" as used in this application refers to the physical state of a compound after the compound has been isolated in a synthetic process (e.g., from a reaction mixture), from a natural source, or a combination thereof. The term "in substantially purified form" also refers to the physical state of a compound after the compound has been obtained using a purification method or methods described herein or well known to those skilled in the art (e.g., chromatography, recrystallization, etc.) with sufficient purity to be characterized by standard analytical methods described herein or well known to those skilled in the art.

It should also be noted that any carbon, as well as heteroatom with unsaturated valence in the text, diagrams, examples and tables in this application, is assumed to have a sufficient number of hydrogen atoms to saturate the valence.

When a functional group in a compound is called "protected," it means that the group is in a modified form to prevent unwanted side reactions at the protected site when the compound undergoes a reaction. Suitable protecting groups will be known to those skilled in the art and can be found in standard references, such as T.W. Greene et al ., Protective Groups in Organic Synthesis (1991), Wiley, New York.

When any substituent or variable (e.g., R ⁴ ) occurs more than once in any component or in Formula (I), its definition in each occurrence is independent of its definition in every other occurrence, unless otherwise stated.

As used in this application, the term “composition” is intended to encompass a product containing the stated ingredients in the stated amounts, as well as any product resulting from a combination of the stated ingredients in the stated amounts.

The compounds of the present invention are prodrugs of (11aS,11bR)-N-(3-chloro-2-fluorobenzyl)-5-hydroxy-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizine-3-carboxamide, which is also referred to as Compound A and has the following chemical structure:

.

The synthesis and ability of (11aS,11bR)-N-(3-chloro-2-fluorobenzyl)-5-hydroxy-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizine-3-carboxamide to inhibit HIV integrase are described in International PCT Application WO2018/102485, published June 7, 2018 by Merck Sharp & Dohme Corp., which is incorporated herein by reference in its entirety.

The term "prodrug" refers to a compound (e.g., a drug precursor) that is transformed in vivo to form a pharmacologically active compound or a pharmaceutically acceptable salt of the compound. Transformation can occur through various mechanisms (e.g., metabolic or chemical processes), such as hydrolysis in the blood.

Solvates of the compounds of the invention are also provided by the present invention.

One or more compounds of the invention may exist in unsolvated as well as solvated forms with pharmaceutically acceptable solvents such as water, ethanol, and the like, and the invention is intended to encompass both solvated and unsolvated forms. "Solvate" means a physical association of a compound of the present invention with one or more solvent molecules. This physical association includes varying degrees of ionic and covalent bonding, including hydrogen bonding. In some situations, a solvate may be isolated, such as when one or more solvent molecules are incorporated into the crystal lattice of a crystalline solid. "Solvate" includes both solution-phase solvates and isolable solvates. Non-limiting examples of solvates include ethanolates, methanolates, and the like. "Hydrate" is a solvate in which the solvent molecule is water.

One or more compounds of the invention can optionally be converted into solvates. The preparation of solvates is well known. For example, M. Caira et al ., J. Pharmaceutical Sci ., 93(3) , 601-611 (2004) describe the preparation of solvates of the antifungal fluconazole in ethyl acetate, as well as from water. Similar preparations of solvates, hemisolvates, hydrates, etc. are described by E.C. van Tonder et al ., AAPS PharmSciTechours. , 5(1) , article 12 (2004); and A.L. Bingham et al ., Chem. Commun ., 603-604 (2001). A typical, non-limiting method involves dissolving the compound of the invention in the desired amounts of the desired solvent (organic or water, or mixtures thereof) at above room temperature and cooling the solution at a rate sufficient to form crystals, which are then isolated by standard methods. Analytical methods, such as IR spectroscopy, reveal the presence of the solvent (or water) in the crystals as a solvate (or hydrate).

Tetracyclic heterocyclic compounds can form salts, which are also within the scope of the present invention. Reference to a tetracyclic heterocyclic compound in the present application is intended to include reference to its salts, unless otherwise indicated. The term "salt(s)" as used herein means acidic salts formed with inorganic and/or organic acids, as well as basic salts formed with inorganic and/or organic bases. Furthermore, when a tetracyclic heterocyclic compound contains both a basic moiety, such as, but not limited to, pyridine or imidazole, and an acidic moiety, such as, but not limited to, a carboxylic acid, zwitterions ("inner salts") can be formed and are included within the term "salt(s)" as used herein. In one embodiment, the salt is a pharmaceutically acceptable (i.e., non-toxic, physiologically acceptable) salt. In another embodiment, the salt is not a pharmaceutically acceptable salt. Salts of the compounds of formula (I) can be formed, for example, by reacting a tetracyclic heterocyclic compound with an amount of an acid or base, for example an equivalent amount, in a medium such as a medium in which the salt precipitates, or in an aqueous medium, followed by lyophilization.

Examples of acid addition salts include acetates, ascorbates, benzoates, benzenesulfonates, bisulfates, borates, butyrates, citrates, camphorates, camphorsulfonates, fumarates, hydrochlorides, hydrobromides, hydroiodides, lactates, maleates, methanesulfonates, naphthalenesulfonates, nitrates, oxalates, phosphates, propionates, salicylates, succinates, sulfates, tartrates, thiocyanates, toluenesulfonates (also known as tosylates), and the like. Furthermore, acids generally considered suitable for the formation of pharmaceutically useful salts from parent pharmaceutical compounds are discussed, for example, in P. Stahl et al , Camille G. (eds.) Handbook of Pharmaceutical Salts. Properties, Selection and Use. (2002) Zurich: Wiley-VCH; S. Berge et al. , Journal of Pharmaceutical Sciences (1977) 66(1) 1-19; P. Gould, International J. of Pharmaceutics (1986) 33 201-217; Anderson et al ., The Practice of Medicinal Chemistry (1996), Academic Press, New York; and in The Orange Book (Food and Drug Administration, Washington, DC, on their website). These disclosures are incorporated herein by reference.

Examples of basic salts include ammonium salts, alkali metal salts such as sodium, lithium and potassium salts, alkaline earth metal salts such as calcium and magnesium salts, salts with organic bases (e.g. organic amines) such as dicyclohexylamine, tert-butylamine, choline, and salts with amino acids such as arginine, lysine, etc. Basic nitrogen-containing groups can be quaternized with agents such as lower alkyl halides (e.g. methyl, ethyl and butyl chlorides, bromides and iodides), dialkyl sulfates (e.g. dimethyl, diethyl and dibutyl sulfates), long-chain halides (e.g. decyl, lauryl and stearyl chlorides, bromides and iodides), arylalkyl halides (e.g. benzyl and phenethyl bromides), etc.

All such acid and base salts are intended to be pharmaceutically acceptable salts within the scope of the invention, and all acid and base salts are considered equivalent to the free forms of the corresponding compounds for the purposes of the invention.

Mixtures of diastereomers can be separated into their individual diastereomers based on their physicochemical differences by methods well known to those skilled in the art, such as, for example, chromatography and/or fractional crystallization. Enantiomers can be separated by converting an enantiomeric mixture into a diastereomeric mixture by reaction with a suitable optically active compound (e.g., a chiral auxiliary such as a chiral alcohol or Mosher acid chloride), separating the diastereomers, and converting (e.g., by hydrolysis) the individual diastereomers into the corresponding pure enantiomers. Stereochemically pure compounds can also be obtained using chiral starting materials or by using salt resolution techniques. Furthermore, some tetracyclic heterocyclic compounds can be atropisomers (e.g., substituted biaryls) and are considered part of the present invention. Enantiomers can also be separated directly using chiral chromatography techniques.

It is also possible that tetracyclic heterocyclic compounds may exist in various tautomeric forms, and all such forms are encompassed within the scope of the invention. For example, all keto-enol and imine-enamine forms of the compounds are included within the invention.

Unless otherwise specified, all stereoisomers (e.g., geometric isomers, optical isomers, and the like) of the compounds of the present invention (including salts, solvates, hydrates, esters, and prodrugs of the compounds, as well as salts, solvates, and esters of prodrugs), such as those that may exist due to asymmetric carbon atoms on the various substituents, including enantiomeric forms (which may exist even in the absence of asymmetric carbon atoms), rotameric forms, atropisomers, and diastereomeric forms, are intended to be encompassed within the scope of the present invention. Where a tetracyclic heterocyclic compound includes a double bond or a fused ring, both the cis and trans forms, as well as mixtures thereof, are encompassed within the scope of the invention.

When a substituent on a chiral carbon atom is shown without defined stereochemistry (using a direct bond to the chiral center), it is understood that both the alpha and beta configurations of the indicated group of substituents are to be considered part of the present invention. For example, it is understood that a compound of the present invention shown as follows:

,

encompasses both stereoisomers at the specified chiral center, the structures of which are as follows:

And

.

NC bond in a “right-handed” condensed ring compounds of formula (I) can exist in any viable orientation.

In the Examples section below, compounds of the present invention that have been purified as individual stereoisomers are sometimes depicted in non-stereospecific form, but are identified using one or more of the terms: “diastereomer 1,” “diastereomer 2,” “isomer 1,” “isomer 2,” “enantiomer A,” and “enantiomer B.” In this case, the absolute stereochemistry of each isolated diastereomer and enantiomeric center has not been determined, and the terms used above are used to represent each individual purified stereochemically pure compound.

Individual stereoisomers of the compounds of the invention may, for example, be substantially free of other isomers or may be mixed, for example, as racemates or with all other, or other selected, stereoisomers. The chiral centers of the present invention may have the S or R configuration as defined in the IUPAC Recommendations of 1974. The use of the terms "salt," "solvate," and the like applies equally to salts and solvates of enantiomers, stereoisomers, rotamers, tautomers, or racemates of the compounds of the invention.

In the compounds of formula (I), the atoms may exhibit their natural isotopic abundance, or one or more atoms may be artificially enriched in a particular isotope having the same atomic number but an atomic mass or mass number different from the atomic mass or mass number predominantly found in nature. The present invention is intended to include all suitable isotopic variations of the compounds of general formula I. For example, the various isotopic forms of hydrogen (H) include protium ( ¹ H) and deuterium ( ² H). Protium is the predominant isotope of hydrogen found in nature. Deuterium enrichment may provide certain therapeutic advantages, such as increased half-life in vivo or reduced dosage requirements, or may provide a compound useful as a standard for characterizing biological samples. Isotopically enriched compounds of formula (I) can be prepared without undue experimentation by conventional methods well known to those skilled in the art, or by methods analogous to those described in the Schemes and Examples herein, using appropriate reagents and/or isotopically enriched intermediates. In one embodiment, in a compound of formula (I), one or more hydrogen atoms are replaced by deuterium.

Tetracyclic heterocyclic compounds may be useful in human and veterinary medicine for the treatment or prevention of HIV infection in a subject. In one embodiment, the tetracyclic heterocyclic compounds may be inhibitors of HIV viral replication. In a specific embodiment, the tetracyclic heterocyclic compounds are inhibitors of HIV-1. Accordingly, tetracyclic heterocyclic compounds may be useful for the treatment of HIV infections and AIDS. According to the invention, the tetracyclic heterocyclic compounds can be administered to a subject in need of treatment or prevention of HIV infection.

Accordingly, in one embodiment, the invention provides methods for treating HIV infection in a subject, comprising administering to the subject an effective amount of at least one tetracyclic heterocyclic compound or a pharmaceutically acceptable salt thereof. In a specific embodiment, the present invention provides methods for treating AIDS in a subject, comprising administering to the subject an effective amount of at least one tetracyclic heterocyclic compound or a pharmaceutically acceptable salt thereof.

Compounds of formula (I)

The present invention provides tetracyclic heterocyclic compounds of formula (I):

(I)

or their pharmaceutically acceptable salts,

Where:

R ¹ is CHR ² -OC(O)-YR ³ , C(O)-C ₁ -C ₁₀ alkyl, CHR ² -OP(O)(OH) ₂ or

;

Y represents a bond or -O-;

R ² is hydrogen or C ₁ -C ₆ alkyl;

R ³ is selected from the group consisting of C ₁ -C ₆ alkyl, (CH ₂ ) _x -OC ₁ -C ₆ alkyl and (CH ₂ ) _x -NR ⁴ R ⁵ , wherein said C ₁ -C ₆ alkyl group may be optionally substituted with one to three groups independently selected from the group consisting of halogen, hydroxy, methoxy and ethoxy;

R ⁴ is hydrogen or C ₁ -C ₆ alkyl;

R ⁵ is hydrogen or C ₁ -C ₆ alkyl;

x is an integer between one and four.

In an embodiment of the present invention, R ¹ is CHR ² -OC(O)-YR ³ . In another embodiment of the present invention, R ¹ is C(O)-C ₁ -C ₁₀ alkyl. In another embodiment of the present invention, R ¹ is CHR ² -OP(O)(OH) ₂ . In another embodiment of the present invention, R ¹ is In one class of embodiment, R ¹ is selected from:

.

In one subclass of embodiment, R ¹ is .

In one embodiment of the present invention, R ² is hydrogen or methyl. In one class of embodiment, R ² is hydrogen. In another class of embodiment, R ² is methyl.

In one embodiment, R ³ is C ₁ -C ₆ alkyl that is optionally substituted with one to three groups independently selected from the group consisting of halogen, hydroxy, methoxy, and ethoxy. In another embodiment, R ³ is (CH ₂ ) _x -OC ₁ -C ₆ alkyl. In another embodiment, R ³ is (CH ₂ ) _x -NR ⁴ R ⁵ .

In one embodiment of the invention, R ⁴ is methyl.

In one embodiment of the invention, R ⁵ is methyl.

In one embodiment, Y is -O-. In another embodiment, Y is a bond.

In one embodiment, x is one. In another embodiment, x is two. In another embodiment, x is three. In another embodiment, x is four.

In another embodiment, the compounds of formula (I) are presented in substantially purified form.

It should be understood that any of the above embodiments may be combined with one or more individual embodiments.

Other embodiments of the present invention include the following:

(a) A pharmaceutical composition comprising an effective amount of a compound of formula (I) and a pharmaceutically acceptable carrier.

(b) The pharmaceutical composition of paragraph (a), further comprising a second therapeutic agent selected from the group consisting of antiviral agents against HIV, immunomodulators, and anti-infective agents.

(c) The pharmaceutical composition of paragraph (b), wherein the antiviral agent against HIV is an antiviral agent selected from the group consisting of HIV NRTIs (nucleoside reverse transcriptase inhibitors) and HIV NNRTIs (non-nucleoside reverse transcriptase inhibitors).

(d) A pharmaceutical combination that is (i) a compound of formula (I) and (ii) a second therapeutic agent selected from the group consisting of antiviral agents against HIV, immunomodulators and anti-infective agents; wherein the compound of formula (I) and the second therapeutic agent are used in an amount that makes the combination effective for inhibiting the replication of HIV, or for treating HIV infection, and/or reducing the likelihood or severity of symptoms of HIV infection.

(e) The combination of (d), wherein the HIV antiviral agent is an antiviral agent selected from the group consisting of HIV NRTIs (nucleoside reverse transcriptase inhibitors) and HIV NNRTIs (non-nucleoside reverse transcriptase inhibitors).

(f) A method for inhibiting HIV replication in a subject in need thereof, which comprises administering to the subject an effective amount of a compound of formula (I).

(g) A method for treating HIV infection and/or reducing the likelihood or severity of symptoms of HIV infection in a subject in need thereof, which comprises administering to the subject an effective amount of a compound of formula (I).

(h) The method of paragraph (g), wherein the compound of formula (I) is administered in combination with an effective amount of at least one second therapeutic agent selected from the group consisting of antiviral agents against HIV, immunomodulators and anti-infective agents.

(i) The method of paragraph (h), wherein the anti-HIV antiviral agent is an antiviral agent selected from the group consisting of HIV NRTIs (nucleoside reverse transcriptase inhibitors) and HIV NNRTIs (non-nucleoside reverse transcriptase inhibitors).

(j) A method for inhibiting HIV replication in a subject in need thereof, which comprises administering to the subject a pharmaceutical composition according to paragraph (a), (b) or (c), or a combination according to paragraph (d) or (e).

(k) A method for treating HIV infection and/or reducing the likelihood or severity of symptoms of HIV infection in a subject in need thereof, which comprises administering to the subject a pharmaceutical composition according to paragraph (a), (b) or (c), or a combination according to paragraph (d) or (e).

Additional embodiments of the present invention include the following:

(l) A pharmaceutical composition comprising an effective amount of a pharmaceutically acceptable salt of a compound of formula (I) and a pharmaceutically acceptable carrier.

(m) The pharmaceutical composition of paragraph (l), further comprising a second therapeutic agent selected from the group consisting of antiviral agents against HIV, immunomodulators, and anti-infective agents.

(n) The pharmaceutical composition of (m), wherein the HIV antiviral agent is an antiviral agent selected from the group consisting of HIV NRTIs (nucleoside reverse transcriptase inhibitors) and HIV NNRTIs (non-nucleoside reverse transcriptase inhibitors).

(o) A pharmaceutical combination that is (i) a pharmaceutically acceptable salt of a compound of formula (I) and (ii) a second therapeutic agent selected from the group consisting of antiviral agents against HIV, immunomodulators and anti-infective agents; wherein the pharmaceutically acceptable salt of the compound of formula (I) and the second therapeutic agent are used in an amount that makes the combination effective for inhibiting the replication of HIV, or for treating HIV infection, and/or reducing the likelihood or severity of symptoms of HIV infection.

(p) The combination of (o), wherein the HIV antiviral agent is an antiviral agent selected from the group consisting of HIV NRTIs (nucleoside reverse transcriptase inhibitors) and HIV NNRTIs (non-nucleoside reverse transcriptase inhibitors).

(q) A method for inhibiting HIV replication in a subject in need thereof, which comprises administering to the subject an effective amount of a pharmaceutically acceptable salt of a compound of formula (I).

(r) A method for treating HIV infection and/or reducing the likelihood or severity of symptoms of HIV infection in a subject in need thereof, which comprises administering to the subject an effective amount of a pharmaceutically acceptable salt of a compound of formula (I).

(s) The method of paragraph (r), wherein the pharmaceutically acceptable salt of the compound of formula (I) is administered in combination with an effective amount of at least one second therapeutic agent selected from the group consisting of antiviral agents against HIV, immunomodulators and anti-infective agents.

(t) The method of paragraph (s), wherein the antiviral agent against HIV is an antiviral agent selected from the group consisting of HIV NRTIs (nucleoside reverse transcriptase inhibitors) and HIV NNRTIs (non-nucleoside reverse transcriptase inhibitors).

(u) A method for inhibiting HIV replication in a subject in need thereof, which comprises administering to the subject a pharmaceutical composition according to paragraph (l), (m) or (n) or a combination according to paragraph (o) or (p).

(v) A method for treating HIV infection and/or reducing the likelihood or severity of symptoms of HIV infection in a subject in need thereof, which comprises administering to the subject a pharmaceutical composition according to paragraph (l), (m) or (n), or a combination according to paragraph (o) or (p).

Other embodiments of the present invention include the following:

(w) A pharmaceutical composition comprising an effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier.

(x) The pharmaceutical composition of paragraph (w), further comprising a second therapeutic agent selected from the group consisting of antiviral agents against HIV, immunomodulators, and anti-infective agents.

(y) The pharmaceutical composition of item (x), wherein the anti-HIV antiviral agent is an antiviral agent selected from the group consisting of HIV NRTIs (nucleoside reverse transcriptase inhibitors) and HIV NNRTIs (non-nucleoside reverse transcriptase inhibitors).

(z) A pharmaceutical combination that is (i) a compound of formula (I) and (ii) or a pharmaceutically acceptable salt thereof, a second therapeutic agent selected from the group consisting of antiviral agents against HIV, immunomodulators and anti-infective agents; wherein the compound of formula (I) and the second therapeutic agent are used in an amount that makes the combination effective for inhibiting the replication of HIV, or for treating HIV infection, and/or reducing the likelihood or severity of symptoms of HIV infection.

(aa) The combination of (z), wherein the HIV antiviral agent is an antiviral agent selected from the group consisting of HIV protease inhibitors and NNRTI HIV inhibitors.

(bb) A method for inhibiting HIV replication in a subject in need thereof, which comprises administering to the subject an effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof.

(cc) A method for treating HIV infection and/or reducing the likelihood or severity of symptoms of HIV infection in a subject in need thereof, which comprises administering to the subject an effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof.

(dd) The method of paragraph (cc), wherein the compound of formula (I) or a pharmaceutically acceptable salt thereof is administered in combination with an effective amount of at least one second therapeutic agent selected from the group consisting of antiviral agents against HIV, immunomodulators and anti-infective agents.

(ee) The method of paragraph (dd), wherein the anti-HIV antiviral agent is an antiviral agent selected from the group consisting of HIV NRTIs (nucleoside reverse transcriptase inhibitors) and HIV NNRTIs (non-nucleoside reverse transcriptase inhibitors).

(ff) A method for inhibiting HIV replication in a subject in need thereof, which comprises administering to the subject a pharmaceutical composition according to paragraph (w), (x) or (y), or a combination according to paragraph (z) or (aa).

(gg) A method for treating HIV infection and/or reducing the likelihood or severity of symptoms of HIV infection in a subject in need thereof, which comprises administering to the subject a pharmaceutical composition according to paragraph (w), (x) or (y), or a combination according to paragraph (z) or (aa).

The present invention also includes a compound of the present invention for use in (i) (ii) as a medicament for use in, or (iii) for the preparation of a medicament for use in: (a) medicine; (b) inhibiting HIV replication, or (c) treating HIV infection and/or reducing the likelihood or severity of symptoms of HIV infection. In these applications, the compounds of the present invention may optionally be used in combination with one or more second therapeutic agents selected from HIV antiviral agents, anti-infective agents, and immunomodulators.

Additional embodiments of the present invention include the pharmaceutical compositions, combinations, and methods described in paragraphs (a)-(gg) above, and the uses described in the preceding paragraph, wherein the compound of the present invention used therein is a compound of one of the embodiments, aspects, classes, subclasses, or with the characteristic features of the compounds described above. In all of these embodiments, the compound may optionally be used in the form of a pharmaceutically acceptable salt or hydrate, where appropriate.

Furthermore, it should be understood that the embodiments of the compositions and methods presented in paragraphs (a)-(gg) above include all embodiments of the compounds, including those embodiments that result from combinations of embodiments.

Non-limiting examples of compounds of formula (I) include compounds 1-8 described in the Examples below and pharmaceutically acceptable salts thereof.

Methods for preparing compounds of formula (I)

Compounds of formula (I) can be prepared from known or readily obtainable starting materials by methods known to those skilled in the art of organic synthesis. Methods applicable to the preparation of compounds of formula (I) are presented in the Examples below and are summarized in the Schemes below. Alternative synthetic routes and analogous structures will be apparent to those skilled in the art of organic synthesis.

Abbreviations and acronyms used in this application include the following:

Ac acetyl Me methyl aq. water MeCN acetonitrile AUC area under the curve MeOH methanol Bu butyl mg milligrams Bz benzoyl MHz megahertz DCM dichloromethane min minutes DHP 3,4-dihydro-2H-pyran µl microliters DIEA or Hunig's base N,N -diisopropylethylamine ml milliliters DMAP 4-dimethylaminopyridine mmol millimole DMF dimethylformamide MS mass spectrometry DMSO dimethyl sulfoxide NaI sodium iodide Et ethyl NMR nuclear magnetic resonance spectroscopy EtOH ethanol Ph phenyl EtOAc ethyl acetate By oral G grams PTSA para-toluenesulfonic acid GI gastrointestinal Pr drank h hour RP reverse phase HCl hydrochloric acid K.T. or k.t. room temperature (ambient, about 25°C) HIV Human immunodeficiency virus sat or sat'd saturated HPLC high-performance liquid chromatography SFC supercritical fluid chromatography Hz hertz tBu tert -butyl IPA isopropanol TEA triethylamine (Et ₃ N) intravenously intravenous TEMED tetramethylethylenediamine iPr isopropyl TFA trifluoroacetic acid K ₂ CO ₃ potassium carbonate THF tetrahydrofuran KI potassium iodide TMS tetramethylsilane l liter ZhKhSD ultra-high-pressure liquid chromatography ZhX liquid chromatography UV ultraviolet LC/MS liquid chromatography/mass spectrometry UV/VIS ultraviolet/visible

General procedures

The starting materials and intermediates were purchased or prepared using known procedures or otherwise, as illustrated. The general method used for the synthesis of compounds of Formula I is described in the following Schemes. In some cases, the order of reaction steps in the Schemes may be varied to facilitate the reaction or avoid unwanted reaction products.

Moisture- or air-sensitive reactions were carried out under nitrogen or argon using anhydrous solvents and reagents. Reaction progress was monitored either by analytical thin-layer chromatography (TLC), typically performed on pre-coated E. Merck silica gel 60F-254 TLC plates, 0.25 mm layer thickness, or by liquid chromatography-mass spectrometry (LC/MS).

The LC/MS system typically used consisted of a Waters ZQ™ platform with electrospray ionization in positive ion detection mode and a Waters Acquity™ Ultra Performance LC system with an autosampler. The column typically used was a Waters Acquity UPLC® BEH C18 1.0×50 mm, 1.7 μm column. The flow rate was 1 mL/min, and the injected sample volume was 10 μL. UV detection was in the 210–400 nm range. The mobile phase consisted of solvent A (water plus 0.05% TFA) and solvent B (MeCN plus 0.05% TFA) with a gradient from 100% solvent A over 0.7 min to 100% solvent B over 3.75 min, held for 1.1 min, then returning to 100% solvent A over 0.2 min.

Preparative HPLC purification was typically performed using a system without mass control. Typically, this was performed on a Teledyne ISCO ACCQPrep HP150 UV system configured with ELSD, UV-triggered collection (254 and 215 nm), and ELSD, and an XBridge™ C-18 5 micron OBD™ column, 30 mm (id) × 250 mm. Mobile phases were mixtures of acetonitrile (10-100%) in water containing 0.1% TFA. Flow rates were maintained at 50 mL/min, injection volumes ranged from 1500 to 8000 µL, and the UV detection range was 210-400 nm. Mobile phase gradients were optimized for individual compounds. Flash chromatography was routinely performed on an ISCO CombiFlash® Rf or ISCO CombiFlash® Companion XL on silica gel (32–63 μM, 60 Å pore size) in prepackaged RediSep® High Performance Gold cartridges of the specified size. ¹ H NMR spectra were acquired on spectrometers operating at 500 MHz in _CDCl3 solutions unless otherwise noted. Chemical shifts are expressed in parts per million (ppm). Tetramethylsilane (TMS) was used as an internal standard in _CD3Cl solutions, and the residual _CH3OH or TMS peak was used as an internal standard in _CD3OD solutions. Coupling constants (J) are reported in hertz (Hz).

Several methods for preparing the compounds of the present invention are also described in the Examples. The starting materials and intermediates were purchased commercially from general catalog sources or prepared using known procedures or otherwise, as illustrated.

Obtaining an intermediate compound

INTERMEDIATE COMPOUND A

Stage 1:

iodomethyl (4-nitrophenyl) carbonate (INTERMEDIATE A)

To a solution of chloromethyl (4-nitrophenyl) carbonate (10.0 g, 43.2 mmol) in acetone (43.2 mL) was added sodium iodide (9.7 g, 64.8 mmol) at 25 °C. The solution was stirred at 40 °C overnight. The reaction mixture was cooled to room temperature and then filtered. The filtrate was concentrated. The residue was dissolved in EtOAc (150 mL) and washed with saturated sodium thiosulfate solution (50 mL). The organic layer was then washed with saturated brine (30 mL), dried (MgSO ₄ ), filtered, and concentrated to give iodomethyl (4-nitrophenyl) carbonate (INTERMEDIATE A). This material was used further without purification.

Obtaining Example Connections

EXAMPLE 1

(((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)methyl (2-methoxyethyl)carbonate

To a mixture of (11aS,11bR)-N-(3-chloro-2-fluorobenzyl)-5-hydroxy-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizine-3-carboxamide ( Compound A ) (10.0 g, 22.33 mmol) and chloromethyl 2-methoxyethyl carbonate (5.65 g, 33.5 mmol) in acetonitrile (112 mL) were added potassium carbonate (9.26 g, 67 mmol), potassium iodide (11.12 g, 67 mmol) and 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) (0.59 g, 2.23 mmol). The resulting mixture was stirred at 80°C until the reaction was complete according to LC-MS (5 h). The reaction mixture was cooled to ambient temperature, diluted with DCM (200 mL) and MeCN (100 mL), and stirred at the same temperature for 20 min. The mixture was filtered, washing with DCM (200 mL), and the filtrate was concentrated. The residue was taken up in DCM (500 mL) and filtered. The filtrate was purified directly by flash chromatography (330 g RediSep Rf Gold; 0-10% MeOH in DCM over 60 min; the filtrate (DCM) was loaded via a CombiFlash Companion XL pump followed by a gradient program on the CombiFlash Rf) and the pure fractions were concentrated to give (((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)methyl (2-methoxyethyl)carbonate ( Example 1 ). The material was then crystallized from 100% IPA. 1H NMR (500 MHz, Chloroform-d) δ 10.82 (t, J=5.8 Hz, 1H), 7.28 (t, J=9.0 Hz, 4H), 7.02 (td, J=7.9, 0.8 Hz, 1H), 5.91-5.84 (m, 2H), 4.95 (d, J=3.3 Hz, 1H), 4.79 (dd, J=13.2, 4.7 Hz, 1H), 4.65 (qd, J=15.5, 5.9 Hz, 2H), 4.48 (ddd, J=10.8, 6.9, 3.3 Hz, 1H), 4.39-4.27 (m, 2H), 4.22 (dd, J=11.6, 4.8 Hz, 1H), 4.13 (dd, J=19.2, 8.9 Hz, 1H), 3.93 (td, J=12.4, 2.5 Hz, 1H), 3.69-3.58 (m, 2H), 3.36 (s, 3H), 3.31-3.41 (m, 1H), 3.10 (td, J=12.9, 2.9 Hz, 1H), 2.46-2.25 (m, 2H), 2.04 m, 1H), 1.54 (d, J=13.9 Hz, 1H). MSHR (low resolution mass spectrometry) (M+H) ⁺ : 580.3.

EXAMPLE 2

Stage 1:

(((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)methyl (4-nitrophenyl)carbonate

To a mixture of (11aS,11bR)-N-(3-chloro-2-fluorobenzyl)-5-hydroxy-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizine-3-carboxamide ( Compound A ) (7.5 g, 16.8 mmol) and iodomethyl (4-nitrophenyl)carbonate ( Intermediate A) (10.8 g, 33.5 mmol) in acetonitrile (120 mL) was added potassium carbonate (8.0 g, 57.8 mmol). The resulting mixture was stirred at 80°C for 4 h. The reaction mixture was cooled to ambient temperature, diluted with DCM (120 mL) and stirred at the same temperature for 20 min. The mixture was filtered, washing with DCM (100 mL), and the filtrate was concentrated. The residue was taken up in DCM (20 mL) again and directly purified by flash chromatography (330 g RediSep Rf Gold; 0-10% MeOH in DCM over 35 min; CombiFlash Rf system; DP eluted with ~4% MeOH). Pure fractions were combined and concentrated to give (((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)methyl (4-nitrophenyl)carbonate. MCHP (M+H) ⁺ : 643.3.

Stage 2:

(((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)methyl (2-(2-methoxyethoxy)ethyl)carbonate

To a solution of (((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)methyl (4-nitrophenyl)carbonate (6.5 g, 10.1 mmol) in DCM (25.3 mL) was added 2-(2-methoxyethoxy)ethan-1-ol (11.9 mL, 101 mmol) followed by DMAP (0.25 g, 2.0 mmol). The resulting mixture was stirred at room temperature overnight. The reaction mixture was directly purified by flash chromatography (330 g RediSep Rf Gold; 30-100% 3:1 EtOAc/EtOH in hexane for 50 min; CombiFlash Rf system). Some starting material A co-eluted with the desired product 2. Fractions containing 2 were pooled and concentrated. The residue was dissolved in DMSO and purified again by preparative reverse-phase chromatography (Waters XBridge™ 5 micron OBD™ 30×250 mm C18 column; 200-275 mg per injection; 20-80% MeCN/water with 0.1% TFA modifier for 27 min). Pure fractions were neutralized with saturated aqueous sodium bicarbonate, extracted with DCM and concentrated to give (((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)methyl (2-(2-methoxyethoxy)ethyl)carbonate ( Example 2 ). The material was then crystallized from 1:1 heptane/isopropyl acetate (300 mg/mL). ¹ H NMR (500 MHz, Chloroform-d) δ 10.87 (t, J=5.8 Hz, 1H), 7.26 (d, J=7.7 Hz, 2H), 7.03 (t, J=7.9 Hz, 1H), 5.85 (q, J=6.5 Hz, 2H), 4.96 (d, J=3.3 Hz, 1H), 4.76 (dd, J=13.1, 4.3 Hz, 1H), 4.59-4.70 (m, 2H), 4.52 (ddd, J=10.7, 7.0, 3.2 Hz, 1H), 4.39-4.28 (m, 2H), 4.21 (dd, J=11.6, 4.6 Hz, 1H), 4.10 (dd, J=19.1, 9.1 Hz, 1H), 3.93 (td, J=12.4, 2.2 Hz, 1H), 3.74 (t, J=4.9 Hz, 2H), 3.66-3.61 (m, 2H), 3.53 (dd, J=5.5, 3.6 Hz, 2H), 3.37 (s, 3H), 3.33-3.41 (m, 1H), 3.16-3.06 (m, 1H), 2.27-2.43 (m, 2H), 2.02 (m, 1H), 1.55 (d, J=13.7 Hz, 1H). MCHP (M+H) ⁺ : 624.3.

EXAMPLE 3

Stage 1:

(((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)methyl(3-(dimethylamino)propyl)carbonate 2,2,2-trifluoroacetate

To a solution of (((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)methyl (4-nitrophenyl)carbonate (1.09 g, 1.70 mmol) in DCM (8.5 mL) was added 3-(dimethylamino)propan-1-ol (2.97 mL, 25.4 mmol) followed by DMAP (21 mg, 0.17 mmol). The resulting mixture was stirred at room temperature until the reaction was complete (after 3 h, LC-MS analysis showed the reaction to be nearly complete). The mixture was concentrated, the residue was dissolved in DMF and directly purified by preparative reverse phase chromatography (Phenomenex Luna 5 micron 50×250 mm C18 column; 2 injections; 5-70% MeCN/water with 0.1% TFA modifier for 30 min). The pure fractions were combined and concentrated under reduced pressure (azeotropic distillation with MeCN) to give (((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)methyl (3-(dimethylamino)propyl)carbonate 2,2,2-trifluoroacetate. MSNP (M+H) ⁺ : 607.4.

Stage 2:

Ex. No. Structure Name Method(s) used
receipt MSNR
(ESI) [M+1] ⁺ 4 (((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)methylisopropyl carbonate Example 1 564.2 5 (((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)methyl ethyl carbonate Example 1 550.3 6 (((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octages dro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)methylmethylcarbonate Example 1 536.3 7 1-(((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)ethyl isopropyl carbonate Example 1 578.4 8 1-(((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)ethyl ethyl carbonate Example 1 564.3

(((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)methyl (3-(dimethylamino)propyl)carbonate, hydrochloride

To a solution of (((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)methyl(3-(dimethylamino)propyl)carbonate 2,2,2-trifluoroacetate (960 mg, 1.33 mmol) in MeOH (5 mL) was added 4N HCl in dioxane (4.24 mL, 16.95 mmol). The resulting mixture was stirred at room temperature for 5 min. The mixture was concentrated, redissolved in MeOH (5 mL), and again concentrated and dried in vacuo to give (((11aS,11bR)-3-((3-chloro-2-fluorobenzyl)carbamoyl)-4,6-dioxo-1,2,4,6,9,10,11a,11b-octahydro-8H-[1,3]oxazino[2',3':3,4]pyrazino[2,1,6-cd]indolizin-5-yl)oxy)methyl(3-(dimethylamino)propyl)carbonate hydrochloride ( Example 3 ). ¹ H NMR (500 MHz, Methanol-d4) δ 7.40 (t, J=7.6 Hz, 1H), 7.34 (t, J=6.8 Hz, 1H), 7.14 (t, J=7.9 Hz, 1H), 5.83 (d, J=6.8 Hz, 1H), 5.65 (d, J=6.8 Hz, 1H), 5.21 (d, J=3.3 Hz, 1H), 4.74-4.59 (m, 4H), 4.36-4.25 (m, 2H), 4.19 (dd, J=11.4, 4.6 Hz, 1H), 4.07-3.99 (m, 1H), 3.99-3.89 (m, 1H), 3.66 (s, 3H), 3.41-3.33 (m, 2H), 2.90 (d, J=15.6 Hz, 6H), 2.39-2.30 (m, 2H), 2.22-2.11 (m, 2H), 1.98-1.91 (m, 1H), 1.60 (d, J=13.4 Hz, 1H). MCHP (M+H) ⁺ : 607.4.

The compounds shown in the following table were prepared in a manner similar to that described for Examples 1 above, using the appropriate starting materials.

Pharmacokinetic studies in dogs

Male beagle dogs (Marshall Farms) were used for pharmacokinetic studies. The studies were performed in accordance with a protocol approved by WP-IACUC (Animal Procedures Statement #2018-600787-MAR). After an overnight fast, dogs were orally dosed with either Compound A at 10 mg/kg and 25 mg/kg, or one of the corresponding prodrugs at a dose equivalent to 10 mg/kg and 25 mg/kg of Compound A, suspended in either 0.5% methylcellulose with 0.25% sodium lauryl sulfate or 10% Tween 80-5 mM HCl. Food was reintroduced 4 hours post-dose. Blood (0.5 ml) was collected before, 0.25, 0.5, 1, 2, 4, 6, 24, 48, 72, 96, and 168 hours postdose into EDTA-coated collection tubes containing 25 μl of a 2 mM dichlorvos solution in water. The tubes were kept refrigerated until blood collection and during plasma separation. Plasma was separated by centrifugation (2 min at 10,000g). Plasma samples were immediately frozen and stored at -70°C until LC-MS/MS analysis.

Pharmacokinetic parameters for compounds after oral administration to fasted beagle dogs at a dose equivalent to 10 mg/kg compound A, mean [± SD]

Input compound Route of administration The measured connection AUC0-168 hours (µM•hour) Cmax (μM) A Oral A 6133
± 1408 58
± 18 1 Oral A 6870
± 408 74
± 15 2* Oral A 9633
± 2311 134
± 34 3* Oral A 5369
± 1016 65
± 11 4 Oral A 2282
± 249 22
± 0.8 5 Oral A 2595
± 571 41
± 8.4 6 Oral A 6198
± 1436 48
± 6 7 Oral A - - 8 Oral A - - *Pharmacokinetic data for the amorphous prodrug

Pharmacokinetic parameters for compounds after oral administration to fasted beagle dogs at a dose equivalent to 25 mg/kg compound A, mean [± SD]

Input compound Route of administration The measured connection AUC0-168 hours (µM•hour) Cmax (μM) A Oral A 8371
± 386 79
± 17 1 Oral A 13376
± 890 157
± 19 2 Oral A Data is pending Data is pending 3 Oral A - - 4 Oral A - - 5 Oral A - - 6 Oral A 9861
± 968 103
± 7 7 Oral A - - 8 Oral A - -

As shown above, Compounds 1 and 6 , which are representative compounds of the present invention, exhibit increased absorption compared to their metabolite, Compound A.

Treatment or prevention of HIV infection

Tetracyclic heterocyclic compounds may be useful for inhibiting HIV, inhibiting HIV integrase, treating HIV infection, and/or reducing the likelihood or severity of HIV infection symptoms, and inhibiting HIV viral replication and/or HIV viral production in cellular systems. For example, tetracyclic heterocyclic compounds may be useful in treating HIV infection following suspected HIV transmission through methods such as blood transfusion, exchange of bodily fluids, bites, accidental needlestick, or contact with a subject's blood during surgery or other medical procedures.

Accordingly, in one embodiment, the invention provides methods for treating HIV infection in a subject, comprising administering to the subject an effective amount of at least one tetracyclic heterocyclic compound or a pharmaceutically acceptable salt or prodrug thereof. In a specific embodiment, the administered amount is effective to treat or prevent HIV infection in the subject. In another specific embodiment, the administered amount is effective to inhibit HIV viral replication and/or viral production in the subject. In one embodiment, the HIV infection has progressed to AIDS.

Tetracyclic heterocyclic compounds are also useful in the preparation and execution of screening assays for antiviral compounds. For example, tetracyclic heterocyclic compounds can be useful for identifying resistant HIV cell lines carrying mutations, which provide excellent tools for screening more potent antiviral compounds. Furthermore, tetracyclic heterocyclic compounds can be useful for identifying or determining the binding site of other antiviral agents to HIV integrase.

The compositions and combinations of the present invention may be useful for treating a subject suffering from an infection associated with any genotype of HIV.

Combination therapy

In another embodiment, the present methods for treating or preventing HIV infection may further comprise administering one or more additional therapeutic agents that are not tetracyclic heterocyclic compounds.

In one embodiment, the additional therapeutic agent is an antiviral agent.

In another embodiment, the additional therapeutic agent is an immunomodulatory agent, such as an immunosuppressant.

Accordingly, in one embodiment, the present invention provides methods for treating a viral infection in a subject, the method comprising administering to the subject: (i) at least one tetracyclic heterocyclic compound (which may include two or more different tetracyclic heterocyclic compounds), or a pharmaceutically acceptable salt or prodrug thereof, and (ii) at least one additional therapeutic agent that is other than the tetracyclic heterocyclic compound, wherein the administered amounts together are effective to treat or prevent the viral infection.

When administering the combination therapy of the invention to a subject, the therapeutic agents in the combination or the pharmaceutical composition or compositions containing the therapeutic agents may be administered in any order, such as, for example, sequentially, in parallel, together, simultaneously, etc. The amounts of the various active substances in such a combination therapy may be different amounts (different dosages) or the same amounts (the same dosages). Thus, for non-limiting illustrative purposes, the tetracyclic heterocyclic compound and the additional therapeutic agent may be present in fixed amounts (dosage amounts) in a single dosage unit (e.g., in a capsule, tablet, etc.).

In one embodiment, at least one tetracyclic heterocyclic compound is administered at a time when the additional therapeutic agent(s) exhibits its prophylactic or therapeutic effect, or vice versa.

In another embodiment, at least one tetracyclic heterocyclic compound and additional therapeutic agent(s) are administered at doses typically used when such agents are used as monotherapy to treat a viral infection.

In another embodiment, at least one tetracyclic heterocyclic compound and the additional therapeutic agent(s) are administered at doses lower than those typically used when such agents are used as monotherapy to treat a viral infection.

In another embodiment, at least one tetracyclic heterocyclic compound and the additional therapeutic agent(s) act synergistically and are administered at doses lower than those typically used when such agents are used as monotherapy to treat a viral infection.

In one embodiment, at least one tetracyclic heterocyclic compound and additional therapeutic agent(s) are present in the same composition. In one embodiment, the composition is suitable for oral administration. In another embodiment, the composition is suitable for intravenous administration. In another embodiment, the composition is suitable for subcutaneous administration. In yet another embodiment, the composition is suitable for parenteral administration.

Viral infections and virus-related disorders that can be treated or prevented using the combination therapy methods of the present invention include, but are not limited to, those listed above.

In one embodiment, the viral infection is HIV infection.

In another embodiment, the viral infection is AIDS.

At least one tetracyclic heterocyclic compound and additional therapeutic agent(s) may act additively or synergistically. A synergistic combination may allow for the use of lower doses of one or more agents and/or less frequent administration of one or more agents in the combination therapy. A lower dose or less frequent administration of one or more agents may reduce the toxicity of the therapy without reducing the effectiveness of the therapy.

In one embodiment, administration of at least one tetracyclic heterocyclic compound and additional therapeutic agent(s) can inhibit resistance of a viral infection to these agents.

As noted above, the present invention also provides the use of a compound of Formula I with one or more anti-HIV agents. An "anti-HIV agent" is any agent that is directly or indirectly effective in inhibiting HIV reverse transcriptase or another enzyme necessary for HIV replication or infection, treating or preventing HIV infection, and/or treating, preventing, or slowing the onset or progression of AIDS. It is understood that an anti-HIV agent is effective in treating, preventing, or slowing the onset or progression of HIV infection or AIDS and/or diseases or conditions arising from or associated with them. For example, the compounds of the present invention can be effectively administered during the pre- and/or post-infection periods in combination with effective amounts of one or more anti-HIV agents selected from HIV antiviral agents, immunomodulators, anti-infective agents, or vaccines useful for the treatment of HIV infection or AIDS. Suitable antiviral drugs against HIV for use in combination with the compounds of the present invention include, for example, those listed in Table A as follows:

Table A Name Trademark abacavir, ABC Ziagen® abacavir + lamivudine Epzicom® abacavir+lamivudine+zidovudine Trizivir® amprenavir Agenerase® atazanavir Reyataz® AZT, zidovudine, azidothymidine Retrovir® cabotegravir Cabenuva®, Vocabria® darunavir Prezista® ddC, zalcitabine, dideoxycytidine Hivid® ddI, didanosine, dideoxyinosine Videx® ddI (enteric coating) Videx EC® delavirdine, DLV Rescriptor® dolutegravir Tivicay® doravirine Pifeltro® doravirine + lamivudine + tenofovir DF Delstrigo® efavirenz, EFV Sustiva®, Stocrin® efavirenz+emtricitabine+tenofovir DF Atripla® emtricitabine, FTC Emtriva® emtricitabine+tenofovir DF Truvada® emvirin Coactinon® enfuvirtide Fuzeon® enteric-coated didanosine Videx EC® etravirine, TMC-125 Intelence® fosamprenavir calcium Lexiva® indinavir Crixivan® islatravir (EFdA, 4'-ethynyl-2-fluoro-2'-deoxyadenosine) lamivudine, 3TC Epivir® lamivudine+zidovudine Combivir® lenacapavir lopinavir lopinavir+ritonavir Kaletra® maraviroc Selzentry® nelfinavir Viracept® nevirapine, NVP Viramune® rilpivirine, TMC-278 Edurant® ritonavir Norvir® saquinavir Invirase®, Fortovase® stavudine, d4T, didehydrodeoxythymidine Zerit® tenofovir DF (DF=disoproxil fumarate), TDF Viread® tipranavir Aptivus® Some of the drugs listed in the table are used in salt form; for example, abacavir sulfate, indinavir sulfate, atazanavir sulfate, nelfinavir mesylate

In one embodiment, one or more anti-HIV drugs are selected from lamivudine, abacavir, ritonavir, darunavir, atazanavir, emtricitabine, tenofovir, rilpivirine, doravirine, EFdA, and lopinavir.

In another embodiment, the compound of formula (I) is used in combination with lamivudine.

In another embodiment, the compound of formula (I) is used in combination with atazanavir.

In another embodiment, the compound of formula (I) is used in combination with darunavir.

In another embodiment, the compound of formula (I) is used in combination with rilpivirine.

In one embodiment, the compound of formula (I) is used in combination with lamivudine and abacavir.

In another embodiment, the compound of formula (I) is used in combination with islatravir.

In another embodiment, the compound of formula (I) is used in combination with emtricitabine and tenofovir.

In another embodiment, the compound of formula (I) is used in combination with doravirine.

In another embodiment, the compound of formula (I) is used in combination with doravirine, lamivudine and tenofovir DF.

In another embodiment, the compound of formula (I) is used in combination with ritonavir and lopinavir.

In one embodiment, the compound of formula (I) is used in combination with abacavir and lamivudine.

In another embodiment, the compound of formula (I) is used in combination with lopinavir and ritonavir.

In one embodiment, the present invention provides pharmaceutical compositions comprising (i) a compound of formula (I), or a pharmaceutically acceptable salt or prodrug thereof; (ii) a pharmaceutically acceptable carrier; and (iii) one or more additional anti-HIV agents selected from lamivudine, abacavir, ritonavir, islatravir, doravirine, and lopinavir, or a pharmaceutically acceptable salt or prodrug thereof, wherein the amounts of components (i) and (iii) present together are effective for treating or preventing HIV infection or for treating, preventing, or slowing the onset or progression of AIDS in a subject in need thereof.

In another embodiment, the present invention provides a method for treating or preventing HIV infection or for treating, preventing, or slowing the onset or progression of AIDS in a subject in need thereof, which comprises administering to the subject (i) a compound of formula (I) or a pharmaceutically acceptable salt or prodrug thereof and (ii) one or more additional anti-HIV agents selected from lamivudine, abacavir, ritonavir, islatravir, doravirine, and lopinavir or a pharmaceutically acceptable salt or prodrug thereof, wherein the amounts of components (i) and (ii) administered together are effective to treat or prevent HIV infection or to treat, prevent, or slow the onset or progression of AIDS in a subject in need thereof.

It should be understood that the scope of combinations of the compounds of the present invention with anti-HIV agents is not limited to the HIV antiviral drugs listed in Table A, but includes, in principle, any combination with any pharmaceutical composition useful for the treatment or prevention of AIDS. Anti-HIV antiviral agents and other agents will generally be used in these combinations in their usual dosage ranges and regimens known in the art, including, for example, the dosages described in Physicians' Desk Reference , Thomson PDR, Thomson PDR, ^57th edition (2003), the ^58th edition (2004), the ^59th edition (2005), and the like. Dosage ranges for the compound of the invention in these combinations are the same as those indicated above.

The doses and dosing regimen of the other agents used in the combination therapy of the present invention for the treatment or prevention of HIV infection may be determined by the attending physician taking into account the approved doses and dosing regimen indicated in the package insert; the age, sex, and general health of the subject; and the type and severity of the viral infection or associated disease or disorder. When administered in combination, the tetracyclic heterocyclic compound(s) and the other agent(s) may be administered simultaneously (i.e., in the same composition or in separate compositions one after the other) or sequentially. This is particularly useful when the components of the combination are administered according to different administration regimens, for example, one component is administered once a day and the other component is administered every six hours, or when the pharmaceutical compositions are different, for example, one in the form of a tablet and the other in the form of a capsule. Thus, a kit including separate dosage forms is preferred.

Compositions and Introduction

When administered to a subject, tetracyclic heterocyclic compounds can be administered as a component of a composition that includes a pharmaceutically acceptable carrier or excipient. The present invention provides pharmaceutical compositions comprising an effective amount of at least one tetracyclic heterocyclic compound and a pharmaceutically acceptable carrier. In the pharmaceutical compositions and methods of the present invention, the active ingredients are typically administered in admixture with suitable carrier substances suitably selected in accordance with the intended form of administration, i.e., oral tablets, capsules (hard, semi-solid, or liquid filled), powders for solution, oral gels, elixirs, dispersible granules, syrups, suspensions, etc., and in accordance with generally accepted pharmaceutical practice. For example, for oral administration in the form of tablets or capsules, the active component of the drug can be combined with any orally non-toxic pharmaceutically acceptable inert carrier, such as lactose, starch, sucrose, cellulose, magnesium stearate, dicalcium phosphate, calcium sulfate, talc, mannitol, ethyl alcohol (liquid forms), and the like. Solid form preparations include powders, tablets, dispersible granules, capsules, wafers, and suppositories. Powders and tablets can comprise from about 0.5% to about 95% of the composition of the invention. Tablets, powders, wafers, and capsules can be used as solid dosage forms suitable for oral administration.

In addition, suitable binders, lubricants, disintegrating agents, and coloring agents may also be included in the mixture if desired or necessary. Suitable binders include starch, gelatin, natural sugars, corn sweeteners, natural and synthetic gums such as acacia, sodium alginate, carboxymethylcellulose, polyethyleneglycol, and waxes. Lubricants suitable for use in these dosage forms include boric acid, sodium benzoate, sodium acetate, sodium chloride, and the like. Disintegrating agents include starch, methylcellulose, guar gum, and the like. Sweeteners, flavorings, and preservatives may also be included if desired.

Liquid form preparations include solutions, suspensions, and emulsions and may include water or water-propylene glycol solutions for parenteral administration.

Liquid preparations may also include solutions for intranasal administration.

Also included are solid-form preparations intended for conversion, immediately before use, to liquid preparations for oral or parenteral administration. Such liquid forms include solutions, suspensions, and emulsions.

To produce suppositories, a low-melting wax, such as a mixture of fatty acid glycerides or cocoa butter, is first melted, and the active ingredient is homogeneously dispersed in it, for example, by stirring. The melted, homogeneous mixture is then poured into appropriately sized molds and allowed to cool, thereby hardening.

In addition, the compositions of the present invention may be formulated in a sustained release form to provide a controlled rate of release of any one or more components or active ingredients to optimize therapeutic effects, i.e., antiviral activity, etc. Suitable sustained release dosage forms include layered tablets containing layers with different disintegration rates, or controlled release polymer matrices impregnated with active components and shaped as tablets, or capsules containing such impregnated or encapsulated porous polymer matrices.

In one embodiment, one or more tetracyclic heterocyclic compounds are administered orally.

In another embodiment, one or more tetracyclic heterocyclic compounds are administered intravenously.

In one embodiment, a pharmaceutical preparation comprising at least one tetracyclic heterocyclic compound is presented in a unit dosage form. In this form, the preparation is subdivided into unit doses containing effective amounts of the active components.

The compositions can be prepared according to conventional mixing, granulating, or coating methods, respectively, and the compositions of the present invention can contain, in one embodiment, from about 0.1% to about 99% tetracyclic heterocyclic compounds by weight or volume. In various embodiments, the compositions of the invention can contain, in one embodiment, from about 1% to about 70% or from about 5% to about 60% tetracyclic heterocyclic compounds by weight or volume.

Compounds of Formula I can be administered orally in a dosage range of 0.001 to 1000 mg/kg body weight per day per mammal (e.g., human) as a single dose or in divided doses. One dosage range is 0.01 to 500 mg/kg body weight per day orally as a single dose or in divided doses. Another dosage range is 0.1 to 100 mg/kg body weight per day orally as a single dose or in divided doses. For oral administration, the compositions may be presented in the form of tablets or capsules containing from 1.0 to 500 mg of the active ingredient, in particular 1, 5, 10, 15, 20, 25, 50, 75, 100, 150, 200, 250, 300, 400 and 500 milligrams of the active ingredient for symptomatic dose adjustment for the subject to be treated. The specific dose level and dosing frequency for any particular subject may vary and will depend on a variety of factors, including the activity of the particular compound used, the metabolic stability and duration of action of that compound, age, body weight, general health, sex, diet, route and time of administration, rate of elimination, drug combination, severity of the particular condition and the recipient undergoing therapy.

For convenience, the total daily dose can be divided and, if desired, administered in portions throughout the day. In one embodiment, the daily dose is administered in a single portion. In another embodiment, the total daily dose is administered as two divided doses over 24 hours. In another embodiment, the total daily dose is administered as three divided doses over 24 hours. In yet another embodiment, the total daily dose is administered as four divided doses over 24 hours.

Unit doses of tetracyclic heterocyclic compounds can be administered at different frequencies. In one embodiment, the unit dose of the tetracyclic heterocyclic compound can be administered once a day. In another embodiment, the unit dose of the tetracyclic heterocyclic compound can be administered twice a week. In another embodiment, the unit dose of the tetracyclic heterocyclic compound can be administered once a week. In another embodiment, the unit dose of the tetracyclic heterocyclic compound can be administered once every two weeks. In another embodiment, the unit dose of the tetracyclic heterocyclic compound can be administered once a month. In yet another embodiment, the unit dose of the tetracyclic heterocyclic compound can be administered once every two months. In another embodiment, the unit dose of the tetracyclic heterocyclic compound can be administered once every three months. In another embodiment, the unit dose of the tetracyclic heterocyclic compound can be administered once every 6 months. In another embodiment, the unit dose of the tetracyclic heterocyclic compound can be administered once a year.

The amount and frequency of administration of tetracyclic heterocyclic compounds will be adjusted by the treating physician, taking into account factors such as the age, condition, and size of the subject, as well as the severity of the symptoms being treated. Compositions according to the invention may further include one or more additional therapeutic agents selected from those listed above.

Sets

In one aspect, the present invention provides a kit comprising a therapeutically effective amount of at least one tetracyclic heterocyclic compound or a pharmaceutically acceptable salt or prodrug of said compound and a pharmaceutically acceptable carrier, excipient or diluent.

In another aspect, the present invention provides a kit comprising an amount of at least one tetracyclic heterocyclic compound or a pharmaceutically acceptable salt or prodrug of said compound and an amount of at least one additional therapeutic agent as defined above, wherein the amounts of two or more active ingredients result in the desired therapeutic effect. In one embodiment, one or more tetracyclic heterocyclic compounds and one or more additional therapeutic agents are presented in the same container. In one embodiment, one or more tetracyclic heterocyclic compounds and one or more additional therapeutic agents are presented in separate containers.

The present invention should not be limited to the specific embodiments disclosed in the examples, which are intended to illustrate several aspects of the invention, and any embodiments that are functionally equivalent are included within the scope of the present invention. Indeed, various modifications of the invention in addition to those shown and described in this application will become apparent to those skilled in the art and are intended to fall within the scope of the appended claims.

This application makes reference to a number of referenced documents, the entire disclosures of which are incorporated herein by reference.

Claims (10)

1. A compound having the structure: or a pharmaceutically acceptable salt thereof. 2. The compound according to claim 1, having the structure or a pharmaceutically acceptable salt thereof. 3. A pharmaceutical composition for inhibiting HIV integrase, comprising an effective amount of a compound according to any one of claims 1 or 2 or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier. 4. A method for treating HIV infection or treating, preventing or slowing the onset or progression of AIDS in a subject in need thereof, which comprises administering to the subject an effective amount of a compound according to claim 1 or 2 or a pharmaceutically acceptable salt thereof. 5. The method according to paragraph 4, where the subject is a human being. 6. The use of a compound according to claim 1 or 2 or a pharmaceutically acceptable salt thereof for inhibiting HIV integrase, for treating or preventing HIV infection, or for treating, preventing or slowing the onset or progression of AIDS in a subject in need thereof.