WO2007140333A2 - Mononucleoside phosphonate compounds - Google Patents

Abstract

The present invention relates to a mononucleoside phosphonate compound in which the nature of the linkage between the ribosyl or carbocyclic residue and the phosphorous atom of a mononucleotide is modified to include alkylene groups, which improve the stability of the compound. These mononucleoside phosphonate compounds optionally have a degradation-resistant substituent attached on the terminal phosphate. By modification of the linkage and the attachment of the degradation-resistant substituent, the stability of the mononucleoside phosphonate compound significantly improves. The mononucleoside phosphonate compounds of the present invention are useful in preventing and treating diseases or disorders associated with platelet aggregation.

Description

MONONUCLEOSIDE PHOSPHONATE COMPOUNDS

TECHNICAL FIELD The present invention relates to a mononucleoside phosphonate compound, in which the nature of the linkage between the ribosyl or carbocyclic residue and the phosphorous atom of a mononucleotide is modified to improve the stability of the compound. The present invention also relates to methods of using such compounds in the prevention or treatment of diseases or disorders associated with platelet aggregation.

BACKGROUND OF THE INVENTION

Hemostasis is the spontaneous process of stopping bleeding from damaged blood vessels. Precapillary vessels contract immediately when cut; within seconds, thrombocytes, or blood platelets, are bound to the exposed matrix of the injured vessel by a process called platelet adhesion. Platelets also stick to each other in a phenomenon known as platelet aggregation to form a platelet plug to stop bleeding quickly.

An intravascular thrombus results from a pathological disturbance of hemostasis. Platelet adhesion and aggregation are critical events in intravascular thrombosis. Activated under conditions of turbulent blood flow in diseased vessels or by the release of mediators from other circulating cells and damaged endothelial cells lining the vessel, platelets accumulate at a site of vessel injury and recruit further platelets into the developing thrombus. The thrombus can grow to sufficient size to block off arterial blood vessels. Thrombi can also form in areas of stasis or slow blood flow in veins. Venous thrombi can easily detach portions of themselves called emboli that travel through the circulatory system and can result in blockade of other vessels, such as pulmonary arteries. Thus, arterial thrombi cause serious disease by local blockade, whereas venous thrombi do so primarily by distant blockade, or embolization. These conditions include venous thrombosis, thrombophlebitis, arterial embolism, coronary and cerebral arterial thrombosis, unstable angina, myocardial infarction, stroke, cerebral embolism, kidney embolisms and pulmonary embolisms. A number of converging pathways lead to platelet aggregation. Whatever the initial stimulus, the final common event is crosslinking of platelets by binding fibrinogen to a membrane binding site, glycoprotein Ilb/IIIa (GPIIb/IIIa). Compounds that are antagonists for GPIIb/IIIa receptor complex have been shown to inhibit platelet aggregation (U.S. Patent Nos. 6,037,343 and 6,040,317). Antibodies against GPIIb/IIIa have also been shown to have high antiplatelet efficacy (The EPIC investigators, New Engl. J. Med. (1994) 330:956-961). However, this class of antiplatelet agents sometimes causes bleeding problems. Thrombin can produce platelet aggregation largely independently of other pathways but substantial quantities of thrombin are unlikely to be present without prior activation of platelets by other mechanisms. Thrombin inhibitors such as hirudin are highly effective antithrombotic agents. However, functioning as both antiplatelet and anti-coagulant agents, thrombin inhibitors again can produce excessive bleeding. (The TIMI 9a investigators, The GUSTO Iia investigators, Circulation, 90: 1624-1630 (1994); Circulation, 90: 1631-1637 (1994); Neuhaus K. L. et al, Circulation, 90: 1638-1642 (1994))

Various antiplatelet agents have been studied for many years as potential targets for inhibiting thrombus formation. Some agents such as aspirin and dipyridamole have come into use as prophylactic antithrombotic agents, and others have been the subjects of clinical investigations. To date, the powerful agents such as disintegrins, and the thienopyridines ticlopidine and clopidogrel have been shown to have substantial side effects, while agents such as aspirin have useful but limited effectiveness (Hass, et al., N. Engl. J. Med., 321 :501- 507 (1989); Weber, et al., Am. J. Cardiol. 66:1461-1468 (1990); Lekstrom and Bell, Medicine 70:161-177 (1991)). In particular, use of the thienopyridines in antiplatelet therapy has been shown to increase the incidence of potentially life threatening thrombotic thrombocytopenic purpura (Bennett, CL. et al. N. Engl. J. Med, (2000) 342: 1771-1777). Aspirin, which has a beneficial effect on platelet aggregation {Br. Med. J. (1994) 308: 81-106; 159-168), acts by inducing blockade of prostaglandin synthesis. Aspirin has no effect on ADP-induced platelet aggregation, and thus has limited effectiveness on platelet aggregation. Furthermore, its well documented high incidence of gastric side effects limits its usefulness in many patients. Clinical efficacy of some newer drugs, such as ReoPro (7E3), is impressive, but recent trials have found that these approaches are associated with an increased risk of major bleeding, sometimes necessitating blood transfusion (New Engl. J. Med. (1994) 330:956-961). Thus it appears that the ideal "benefit/risk" ratio has not been achieved. Recent studies have suggested that adenosine 5 '-diphosphate (ADP), a common agonist, plays a key role in the initiation and progression of arterial thrombus formation (Bemat, et al, Thromb. Haemostas. (1993) 70:812-826); Maffrand, et ai, Thromb. Haemostas. (1988) 59:225-230; Herbert, et al, Arterioscl. Thromb. (1993) 13:1171-1179). ADP induces platelet aggregation, shape change, secretion, influx and intracellular mobilization of Ca⁺², and inhibition of adenylyl cyclase. Binding of ADP to platelet receptors is required for elicitation of the ADP-induced platelet responses. There are at least three P2 receptors expressed in human platelets: a cation channel receptor P2X], a G protein-coupled receptor P2Yi, and a G protein-coupled receptor P2Yi₂ (also referred to as P2Y_ac and P2j ). The P2Xi receptor is responsible for rapid calcium influx and is activated by ATP and by ADP. However, its direct role in the process of platelet aggregation is unclear. The P2Yi receptor is responsible for calcium mobilization, shape change and the initiation of aggregation. P2Yj₂ receptor is responsible for inhibition of adenylyl cyclase and is required for full aggregation. (Hourani, et al, The Platelet ADP Receptors Meeting, La Thuile, Italy, March 29-31, 2000)

Ingall et al (J. Med. Chem. 42: 213-220, (1999)) describe a dose-related inhibition of ADP-induced platelet aggregation by analogues of adenosine triphosphate (ATP), which is a weak, nonselective but competitive P2Yi₂ receptor antagonist. Zamecnik (USPN 5,049,550) discloses a method for inhibiting platelet aggregation in a mammal by administering to said mammal a diadenosine tetraphosphate compound of App(CH₂)ppA or its analogs. Kim et al. (USPN 5,681,823) disclose P¹, P⁴-dithio-P², P³-monochloromethylene 5', 5'" diadenosine P¹, P⁴-tetraphosphate as an antithrombotic agent. The thienopyridines ticlopidine and clopidogrel, which are metabolized to antagonists of the platelet P2Yi₂ receptor, are shown to inhibit platelet function in vivo (Quinn and Fitzgerald, Circulation 100:1667-1672 (1999); Geiger, et al., Arterioscler. Thromb. Vase. Biol. 19:2007-2011 (1999)).

There is an unmet medical need for new therapeutic nucleotides that have good storage stability and/or in vivo stability that can be used for treating diseases or disorders associated with platelet aggregation with minimal side effects. Nucleotides, defined here as a nucleoside base with one or more phosphate groups attached at the furanosyl primary hydroxyl group, can act via receptors (e.g. P2Y), and ion channels (e.g. P2X). The therapeutic utility of nucleotides arises from their actions as either agonists or antagonists of receptor (P2) function. Two classes of therapeutic nucleotides have emerged recently — mononucleotides (e.g. nucleoside mono-, di-, and tri-phosphates) and dinucleotides (dinucleoside polyphosphates). Mononucleotides, such as uridine triphosphate and adenosine triphosphate (UTP and ATP) are potent ligands of P2 receptors (see U.S. Patent Nos. 5,292,498 and 5,628,984). However, these mononucleotides have poor chemical and metabolic stability making them less attractive as drug candidates due to required refrigeration and short in vivo half-life. Dinucleotides, such as diuridine tetraphosphate and diadenosine tretraphosphate (Up₄U and Ap₄A), show an improvement in chemical and metabolic stability (Yerxa, et al. (Drugs of the Future, 24:759-769 (1999)), while retaining activity at various P2 receptors (see U.S. Patent Nos. 5,635,160; 5,837,861; 5,900,407; 6,319,908; and 6,323,187). However, dinucleotides are more difficult and expensive to synthesize.

There is a need in the area of cardiovascular and cerebrovascular therapeutics for a new class of compounds that have good storage stability and/or in vivo stability and can be used for treating diseases or disorders associated with platelet aggregation with minimal side effects.

SUMMARY OF THE INVENTION

The present invention is directed to mononucleoside phosphonate compounds of the general Formula I, or pharmaceutically acceptable salts, hydrates, solvates thereof:

Formula I

wherein A is a covalently bound substituent having a maximum molecular weight of 1000 and is selected from the group consisting of an amino acid, a peptide, a polypeptide, an oligonucleotide, a polynucleotide, a natural or non-natural steroid, ORi, SRi, NRiR₂, and CR]R₂R₃, wherein Ri, R₂, and R₃ are independently M, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, phosphonate, or acylthioalkyl, with or without substituents or heteroatoms; or taken together to form a cycloalkyl or aryl ring, with or without substituents or heteroatoms; in one embodiment, A is a hydroxylated alkyl group (e.g. glycerol, cholesterol); is an amino acid (e.g. phenylalanine, serine, tyrosine); is amino or mono- or disubstituted amino; X₁, X₂, and X₃, are independently oxygen, methylene, monochloromethylene, dichloromethylene, monofluoromethylene, difluoromethylene, or NH;

X₄ is methylene, monochloromethylene, dichloromethylene, monofluoromethylene, difluoromethylene, or absent;

X₅ are is oxygen, methylene, monochloromethylene, dichloromethylene, monofluoromethylene, difluoromethylene, NH, or absent; preferably, when X₅ is oxygen or NH, D is CH₂;

G is oxygen, methylene, monochloromethylene, dichloromethylene, monofluoromethylene, or difluoromethylene; with the proviso that X₄ is not absent when G is oxygen, and G is not oxygen when X₅ is oxygen or NH; q= 0, 1, or 2; with the proviso that G is not oxygen when q= 2; preferably, X₄ is methylene, G is oxygen or methylene, q= 1 , and X₅ is methylene or absent, preferably, when G is oxygen and X₅ is absent, then D is CH₂ m = 0, 1 or 2; n = 0 or l; p - 0, 1, or 2; where the sum of m+n+p is from 0 to 5;

Ti, T₂, W, and V are independently oxygen or sulfur;

M = H or a pharmaceutically-acceptable inorganic or organic counter ion; D = O or CH₂;

B is a purine or a pyrimidine residue according to general Formulae IV and V, respectively, which is linked to the 1 ' position of the furanose or carbocycle via the 9- or 1- position of the base, respectively;

Y = H, OH, or OR₄; Z = H, OH, or OR₅; with the proviso that Y and Z are both not H; R₄ and R₅ are residues which are linked directly to the 2' and /or 3' oxygens of the furanose or carbocycle via a carbon atom according to Formula II, or linked directly to the two 2' and 3' oxygens of the furanose or carbocycle via a common carbon atom according to Formula III. The present invention is also directed to a method of preventing or treating diseases or conditions associated with platelet aggregation. The method comprises administering to a subject in need thereof a therapeutically effective amount of a mononucleoside phosphonate compound according to the present invention, wherein said amount is effective to inhibit platelet aggregation, hi a preferred method, compound reversibly inhibits ADP-induced platelet aggregation.

DETAILED DESCRIPTION OF THE INVENTION Definitions

When present, unless otherwise specified, the following terms are generally defined as, but are not limited to, the following: "Alkyl" groups are from 1 to 12 carbon atoms inclusively, either straight chained or branched, are more preferably from 1 to 8 carbon atoms inclusively, and most preferably 1 to 6 carbon atoms inclusively.

"Alkylene chains" are from 2 to 20 carbon atoms inclusively, have two points of attachment to the to the molecule to which they belong, are either straight chained or branched, can contain one or more double and/or triple bonds, are more preferably from 4 to 18 atoms inclusively, and are most preferably from 6 to 14 atoms inclusively.

"Alkenyl" groups are from 1 to 12 carbon atoms inclusively, either straight or branched containing at least one double bond but can contain more than one double bond.

"Alkynyl" groups are from 1 to 12 carbon atoms inclusively, either straight or branched containing at least one triple bond but can contain more than one triple bond, and additionally can contain one or more double bonded moieties.

"Alkoxy" refers to the group alkyl-O- wherein the alkyl group is as defined above including optionally substituted alkyl groups as also defined above.

"Aryl" refers to an unsaturated aromatic carbocyclic group of from 6 to 14 carbon atoms inclusively having a single ring (e.g., phenyl) or multiple condensed rings (e.g., naphthyl or anthryl). Preferred aryls include phenyl, naphthyl and the like. " Arylalkyl" refers to aryl -alkyl- groups preferably having from 1 to 6 carbon atoms inclusively in the alkyl moiety and from 6 to 10 carbon atoms inclusively in the aryl moiety. Such arylalkyl groups are exemplified by benzyl, phenethyl and the like.

"Arylalkenyl" refers to aryl -alkenyl- groups preferably having from 1 to 6 carbon atoms in the alkenyl moiety and from 6 to 10 carbon atoms inclusively in the aryl moiety. "Arylalkynyl" refers to aryl -alkynyl- groups preferably having from 1 to 6 carbon atoms inclusively in the alkynyl moiety and from 6 to 10 carbon atoms inclusively in the aryl moiety.

"Aryloxy" refers to the group aryl-O- wherein the aryl group is as defined above including optionally substituted aryl groups as also defined above.

"Cycloalkyl" refers to cyclic alkyl groups of from 3 to 12 carbon atoms inclusively having a single cyclic ring or multiple condensed rings which can be optionally substituted with from 1 to 3 alkyl groups. Such cycloalkyl groups include, by way of example, single ring structures such as cyclopropyl, cyclobutyl, cyclopentyl, cyclooctyl, 1 -methyl cyclopropyl, 2- methylcyclopentyl, 2 -methyl cyclooctyl, and the like, or multiple ring structures such as adamantyl, and the like.

"Cycloalkenyl" refers to cyclic alkenyl groups of from 4 to 12 carbon atoms inclusively having a single cyclic ring or multiple condensed rings and at least one point of internal unsaturation, which can be optionally substituted with from 1 to 3 alkyl groups. Examples of suitable cycloalkenyl groups include, for instance, cyclobut-2-enyl, cyclopent-3- enyl, cyclooct-3-enyl and the like.

"Cycloalkylalkyl" refers to cycloalkyl -alkyl- groups preferably having from 1 to 6 carbon atoms inclusively in the alkyl moiety and from 6 to 10 carbon atoms inclusively in the cycloalkyl moiety. Such cycloalkylalkyl groups are exemplified by cyclopropylmethyl, cyclohexylethyl and the like.

"Halo" substituents are taken from fluorine, chlorine, bromine, and iodine. "Heteroaryl" refers to a monovalent aromatic carbocyclic group of from 1 to 10 carbon atoms inclusively and 1 to 4 heteroatoms inclusively selected from oxygen, nitrogen and sulfur within the ring. Such heteroaryl groups can have a single ring (e.g., pyridyl or furyl) or multiple condensed rings (e.g., indolizinyl or benzothienyl). "Heteroarylalkyl" refers to heteroaryl -alkyl- groups preferably having from 1 to 6 carbon atoms inclusively in the alkyl moiety and from 6 to 10 carbon atoms inclusively in the heteroaryl moiety. Such arylalkyl groups are exemplified by pyridylmethyl and the like.

"Heteroarylalkenyl" refers to heteroaryl -alkenyl- groups preferably having from 1 to 6 carbon atoms inclusively in the alkenyl moiety and from 6 to 10 carbon atoms inclusively in the heteroaryl moiety.

"Heteroarylalkynyl" refers to heteroaryl -alkynyl- groups preferably having from 1 to 6 carbon atoms inclusively in the alkynyl moiety and from 6 to 10 carbon atoms inclusively in the heteroaryl moiety. "Heterocycle" refers to a saturated or unsaturated group having a single ring or multiple condensed rings, from 1 to 8 carbon atoms inclusively and from 1 to 4 hetero atoms inclusively selected from nitrogen, sulfur or oxygen within the ring. Such heterocyclic groups can have a single ring (e.g., piperidinyl or tetrahydrofuryl) or multiple condensed rings (e.g., indolinyl, dihydrobenzofuran or quinuclidinyl). Preferred heterocycles include piperidinyl, pyrrolidinyl and tetrahydrofuryl.

Examples of heterocycles and heteroaryls include, but are not limited to, furan, thiophene, thiazole, oxazole, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, indolizine, isoindole, indole, indazole, purine, quinolizine, isoquinoline, quinoline, phthalazine, naphthylpyridine, quinoxaline, quinazoline, cinnoline, pteridine, carbazole, carboline, phenanthridine, acridine, phenanthroline, isothiazole, phenazine, isoxazole, phenoxazine, phenothiazine, imidazolidine, imidazoline, piperidine, piperazine, pyrrolidine, indoline and the like.

Positions occupied by hydrogen in the foregoing groups can be further substituted with substituents exemplified by, but not limited to, hydroxy, oxo, nitro, methoxy, ethoxy, alkoxy, substituted alkoxy, fluoro, chloro, bromo, iodo, methyl, ethyl, propyl, butyl, alkyl, substituted alkyl, thio, thioalkyl, acyl, carboxyl, alkoxycarbonyl, carboxamido, substituted carboxamido, alkylsulfonyl, alkylsulfinyl, alkylsulfonylamino, sulfonamido, substituted sulfonamide, cyano, amino, substituted amino, acylamino, trifluoromethyl, trifiuoromethoxy, phenyl, aryl, substituted aryl, pyridyl, imidazolyl, heteroaryl, substituted heteroaryl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloalkyl, substituted cycloalkyl, pyrrolidinyl, piperidinyl, morpholino, and heterocycle; and preferred heteroatoms are oxygen, nitrogen, and sulfur. It is understood that where open valences exist on these substituents they can be further substituted with alkyl, cycloalkyl, aryl, heteroaryl, and/or heterocycle groups, and where multiple such open valences exist, these groups can be joined to form a ring, either by direct formation of a bond or by formation of bonds to a new heteroatom, preferably oxygen, nitrogen, or sulfur. It is further understood that the above subtitutions can be made provided that replacing the hydrogen with the substituent does not introduce unacceptable instability to the molecules of the present invention, and is otherwise chemically reasonable.

"Pharmaceutically acceptable salts" are salts that retain the desired biological activity of the parent compound and do not impart undesired toxicological effects. Pharmaceutically acceptable salt forms include various polymorphs as well as the amorphous form of the different salts derived from acid or base additions. The acid addition salts can be formed with inorganic or organic acids. Illustrative but not restrictive examples of such acids include hydrochloric, hydrobromic, sulfuric, phosphoric, citric, acetic, propionic, benzoic, napthoic, oxalic, succinic, maleic, malic, adipic, lactic, tartaric, salicylic, methanesulfonic, 2- hydroxyethanesulfonic, toluenesulfonic, benzenesulfonic, camphorsulfonic, and ethanesulfonic acids. The pharmaceutically acceptable base addition salts can be formed with metal or organic counterions and include, but are not limited to, alkali metal salts such as sodium or potassium; alkaline earth metal salts such as magnesium or calcium; and ammonium or tetraalkyl ammonium salts, i.e., NX₄ ⁺ (wherein X is Ci_-4).

"Tautomers" are compounds that can exist in one or more forms, called tautomeric forms, which can interconvert by way of a migration of one or more hydrogen atoms in the compound accompanied by a rearrangement in the position of adjacent double bonds. These tautomeric forms are in equilibrium with each other, and the position of this equilibrium will depend on the exact nature of the physical state of the compound. It is understood that where tautomeric forms are possible, the current invention relates to all possible tautomeric forms.

"Solvates" are addition complexes in which a compound of Formula I or II is combined with a pharmaceutically acceptable cosolvent in some fixed proportion. Cosolvents include, but are not limited to, water, methanol, ethanol, 1-propanol, isopropanol, 1-butanol, isobutanol, tert-butanol, acetone, methyl ethyl ketone, acetonitrile, ethyl acetate, benzene, toulene, xylene(s), ethylene glycol, dichloromethane, 1 ,2-dichloroethane, N- methylformamide, N,N-dimethylformamide, N-methylacetamide, pyridine, dioxane, and diethyl ether . Hydrates are solvates in which the cosolvent is water. It is to be understood that the definition of compounds in Formulae I and II encompasses all possible hydrates and solvates, in any proportion, which possess the stated activity.

One way the chemical and biological stability of a dinucleotide can be achieved by a mononucleotide is to attach a degradation-resistant substituent A to the phosphate of a mononucleoside monophosphate, or to the terminal phosphate of a mononucleoside polyphosphate. By attaching a degradation-resistant substituent, the stability from degradation matches or exceeds that of certain dinucleotides. The pharmacological activity of the mononucleotide is often maintained, or sometimes enhanced, when this degradation- resistant substituent is present.

A second way to impart the chemical and biological stability of a dinucleotide to a mononucleotide is to modify the nature of the linkage between the ribosyl or carbocyclic residue and the phosphorous atom of a mononucleoside monophosphate, or, for mononucleoside polyphosphates, between the the ribosyl or carbocyclic residue and the first phosphorous atom of the polyphosphate chain to include one or more alkylene groups. An advantage of this stabilizing modification over the simple attachment of a degradation- resistant substituent A to the terminal phosphate is that it provides improved biological and chemical stability.

A third way to impart the chemical and biological stability of a dinucleotide to a mononucleotide is to incorporate both a degradation-resistant substituent A to the terminal phosphate of a mononucleotide as well as to modify the nature of the linkage between the ribosyl or carbocyclic residue and the first phosphorous atom in the same mononucleotide. This combined approach in many instances provides enhanced chemical and/or biological stability over each modification alone. Also, the presence of both modifications reduces the number of ionic charges on the phosphate chain, leading to molecules with unique pharmacologic, pharmacokinetic, and/or pharmacodynamic properties.

Important criteria for these new molecules are improved stability and that the above described modifications do not interfere with the activity of the nucleotide. In general, this means that the degradation-resistant substituents A and the modified linkage between the first phosphorous atom and the ribosyl or carbocyclic residue are no larger than 1000 Daltons, and are preferably less than 500 Daltons. It is important that the modifications of the present invention are beneficial and do not adversely affect the pharmacological activity or toxicity of the nucleotides. Furthermore, it is important that nucleotides bearing these modifications are inert towards any ingredient of a pharmaceutical formulation comprising the nucleotides, hi other words, any nucleotide so modified must be stable within a pharmaceutical formulation.

Novel Compounds

The present invention provides mononucleoside phosphonate compounds of Formula I, and/or tautomers thereof, and/or pharmaceutically-acceptable salts, and/or solvates, and/or hydrates thereof:

Formula I

wherein

A is a covalently bound substituent having a maximum molecular weight of 1000 and is selected from the group consisting of an amino acid, a peptide, a polypeptide, an oligonucleotide, a polynucleotide, a natural or non-natural steroid, ORi, SRi, NRjR₂, and CRjR₂R₃, wherein R₁, R₂, and R₃ are independently M, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, phosphonate, or acylthioalkyl, with or without substituents or heteroatoms; or taken together to form a cycloalkyl or aryl ring, with or without substituents or heteroatoms; in one embodiment, A is a hydroxylated alkyl group (e.g. glycerol , cholesterol); is an amino acid (e.g. phenylalanine, serine, tyrosine); is amino or mono- or disubstituted amino; Xi, X₂, and X₃, are independently oxygen, methylene, monochloromethylene, dichloromethylene, monofluoromethylene, difiuoromethylene, or NH; X₄ is methylene, monochloromethylene, dichloromethylene, monofluoromethylene, difluoromethylene, or absent;

X₅ are is oxygen, methylene, monochloromethylene, dichloromethylene, monofluoromethylene, difluoromethylene, NH, or absent; preferably, when X₅ is oxygen or NH, D is CH₂ ;

G is oxygen, methylene, monochloromethylene, dichloromethylene, monofluoromethylene, or difluoromethylene; with the proviso that X₄ is not absent when G is oxygen, and G is not oxygen when X₅ is oxygen or NH; q= 0, 1 , or 2; with the proviso that G is not oxygen when q= 2; preferably, X₄ is methylene, G is oxygen or methylene, q= 1 , and X₅ is methylene or absent, preferably, when G is oxygen and X₅ is absent, then D is CH₂ m = 0, 1 or 2; n = 0 or 1 ; p = 0, 1, or 2; where the sum of m+n+p is from 0 to 5;

T₁, T₂, W, and V are independently oxygen or sulfur;

M = H or a pharmaceutically-acceptable inorganic or organic counter ion;

D = O or CH₂; B is a purine or a pyrimidine residue according to general Formulae IV and V, respectively, which is linked to the 1' position of the furanose or carbocycle via the 9- or 1- position of the base, respectively;

Y = H, OH, or OR₄;

Z = H, OH, or OR₅; with the proviso that Y and Z are both not H; R₄ and R₅ are residues which are linked directly to the 2' and/or 3' oxygens of the furanose or carbocycle via a carbon atom according to Formula II, or linked directly to the two 2' and 3' oxygens of the furanose or carbocycle via a common carbon atom according to Formula III; Formula II

wherein:

O is the corresponding 2' and/or 3' oxygen of the furanose or carbocycle; R₆, R_7> and R₈ are independently H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, with or without substitution, such that the moiety defined according to Formula II is an ether; or R₆ and R₇ are H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, with or without substitution; and R₈ is alkoxy, cycloalkoxy, aralkyloxy, aryloxy, substituted aralkyloxy, or substituted aryloxy, such that the moiety defined according to formula II is an acyclic acetal or ketal; or R₆ and R₇ are taken together as oxygen or sulfur doubly bonded to C, and R₈ is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, with or without substitution, such that the moiety defined according to Formula II is an ester or thioester; or R₆ and R₇ are taken together as oxygen or sulfur doubly bonded to C, and R₈ is amino or mono- or disubstituted amino, where the substituents are alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, with or without substitution, such that the moiety according to Formula II is a carbamate or thiocarbamate; or

R₆ and R₇ are taken together as oxygen or sulfur doubly bonded to C, and R₈ is alkoxy, cycloalkoxy, aralkyloxy, aryloxy, substituted aralkyloxy, or substituted aryloxy, such that the moiety according to Formula II is a carbonate or thiocarbonate; or R₈ is not present and R₆ and R₇ are taken together as oxygen or sulfur doubly bonded to C and both the 2' and 3' oxygens of the furanose are directly bound to C to form a cyclical carbonate or thiocarbonate; Formula III

wherein:

O is the 2' and 3' oxygens of the furanose or carbocycle; and the 2' and 3' oxygens of the furanose or carbocycle are linked by a common carbon atom (C) to form a cyclical acetal, cyclical ketal, or cyclical orthoester; for cyclical acetals and ketals, R₉ and Ri₀ are independently H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, with or without substitution; or can be joined together to form a homocyclic or heterocyclic ring composed of 3 to 8 atoms, preferably 3 to 6 atoms; for cyclical orthoesters, R₉ is H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, with or without substitution; R]₀ is alkyloxy, cycloalkyloxy, aralkyloxy, aryloxy, with or without substitution;

Formula IV

wherein:

Rn and Rj₅ are hydroxy, oxo, amino, mercapto, alkylthio, arylthio, alkyloxy, aryloxy, alkylamino, cycloalkylamino, aralkylamino, arylamino, diaralkylamino, diarylamino, or dialkylamino, where the alkyl groups are optionally linked to form a heterocycle; or Ri i and R₁₅ are acylamino; or when Rn in a purine or R₁₅ in a pyrimidine has as its first atom nitrogen, Ri ₁ and Ri? or Rj₅ and Rj₆ can be taken together to form a 5-membered fused imidazole ring (etheno compounds), optionally substituted on the etheno ring with alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, with or without substitution; or when Rj₅ in a pyrimidine has as its first atom oxygen, Rj₅ and Rj₇ can be taken together to form a 5-membered dihydrofuran ring, optionally substituted on the dihydrofuran ring with alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, with or without substitution; J is carbon or nitrogen, with the provision that when nitrogen, Rj₃ is not present; Ri₂ is hydrogen, O (adenine 1 -oxide derivatives) or is absent (adenine derivatives);

Ri₆ is hydrogen, or acyl (e.g. acetyl, benzoyl, phenylacyl, with or without substituents) or is absent (cytosine derivatives);

Ri₃ is hydrogen, alkyl, bromo, azido, alkylamino, arylamino or aralkylamino, alkoxy, aryloxy or aralkyloxy, alkylthio, arythio or aralkylthio, or CO-E(Ci_-6 alkyl)G-, wherein E and G are independently amino, mercapto, hydroxy or carboxyl;

Ri₄ is hydrogen, halo, amino, monosubstituted amino, disubstituted amino, alkylthio, arylthio, or aralkylthio, where the substituent on sulfur contains up to a maximum of 20 carbon atoms, with or without unsaturation; R₁₇ is hydrogen, halo, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, with or without substitution;

Compounds according to Formulae IV and V, where Ri ₁ or R₁₅ is acylamino for the most part fall within the scope of Formula VI:

Formula VI

wherein NH is the amino residue at the C-6 position in a purine or the amino residue at the C- 4 position in a pyrimidine; W is oxygen or sulfur; and

Ri ₈ is amino or mono- or disubstituted amino such that the moiety according to Formula VI is a urea or thiourea; or Ri g is alkoxy, aralkyloxy, aryloxy, substituted aralkyloxy, or substituted aryloxy, such that the moiety according to Formula VI is a carbamate or thiocarbamate; or Ri g is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, with or without substitution, with or without heteroatoms, such that the moiety according to Formula VI is an amide.

In one embodiment, the compounds of the present invention comprise compounds of Formula I wherein A has a molecular weight of no more than about 1000 and is ORi, SRi, NRjR₂, or CRiR₂R₃ such that R₁, R₂, and R₃ are independently alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, phosphonate, or acylthioalkyl, with or without substituents or heteroatoms; or taken together to form a cycloalkyl or aryl ring, with or without substituents or heteroatoms; or a natural or non- natural amino acid, peptide, polypeptide, or other oligomer; or natural or non-natural steroid. For example, A is a hydroxylated alkyl group (e.g. glycerol, cholesterol); is an amino acid (e.g. phenylalanine, serine, tyrosine); is amino or mono- or disubstituted amino, where the substituents are alkyl, cycloalkyl, aralkyl, aryl, substituted aralkyl, or substituted aryl having 3 to 20 carbon atoms and which may also contain heteroatoms (e.g. S, N, O) with 3 to 15 atoms being most preferred.

In one embodiment, A is CRjR₂R₃, wherein R₁, R₂, and R₃ are independently hydrogen, alkyl, cycloalkyl, aryl, arylalkyl, phosphonate, or acylthioalkyl with or without substituents or heteroatoms; or taken together to form a cycloalkyl or aryl ring, with or without substituents or heteroatoms.

Preferably, CRjR₂R₃ is an alkyl chain of 1-4 carbon atoms, with or without heteroatoms or substituents; or CRiR₂R₃ is a saturated or unsaturated ring of 5 or 6 atoms, with or without heteroatoms or substituents, and with or without a linker of from 1 to 3 atoms between said ring and the phosphorous atom. In one embodiment, X₁, X₂, X₃, X₄, and X₅ are oxygen, dichloromethylene or difluoromethylene; with oxygen being most preferred. In preferred compounds of the present invention, Tj, T₂, W, and V of Formula I are independently oxygen or sulfur. More preferably, Tiand T₂, are sulfur or oxygen, and W and V are oxygen, respectively; with Tj, T₂, W, and V being oxygen being most preferred. In preferred compounds of the present invention, the sum of m+n+p of Formula is from 0 to 4. More preferably, the sum of m+n+p of Formula I is 0-2, with 0 being most preferred. In preferred compounds of the present invention, M is lithium, sodium or potassium; an alkaline earth metal salt such as magnesium or calcium; or an ammonium or tetraalkyl ammonium salt, i.e., NX₄ ⁺ (wherein X is Ci_-4). More preferably M is sodium, potassium, or tetraalkyl ammonium; with sodium being most preferred. In preferred compounds of the present invention, D is oxygen.

In one embodiment, both Y and Z are OH. In another embodiment, Y is OR₄ and Z is OR₅.

In one embodiment, R₄ and R₅ are linked directly to the 2' and/or 3' oxygens of the furanose or carbocycle via a carbon atom according to Formula II, R₆ and R₇ together is oxygen, and R₈ is mono- or di-substituted amino, hi a preferred embodiment, R₄ and R₅ are linked directly to the two 2' and 3' oxygens of the furanose or carbocycle via a common carbon atom according to Formula III, R₉ is H or aralkyl, and Rj₀ is aralkyl.

When B is a purine, it is preferably adenosine or hypoxanthine. Alternatively, Ri 1 is alkylamino or acylamino, Ri₂ is H or absent, Rj₃ is H or halogen, R]₄ is H, halogen, thioalkyl, or thioaralkyl. Preferably Ri₃ is H, R₁₄ is H or thioalkyl,

When B is a pyrimidine, it is preferably undine or cytidine. Alternatively, Ri₅ is O, S, amino, or substituted amino, Ri₆ is H or absent; or Rj₅ and Ri₆ are taken together to form a substituted 5-membered imidazole ring; Rj₇ is H, halogen, alkyl, or substituted alkynyl; and Rig is aralkyloxy. More preferably, Rj₅ is O, S, or amino; or Rj₅ and Ri₆ are taken together to form a substituted 5-membered imidazole ring; and Rj₇ is H, halogen, alkyl, or substituted alkynyl; with Ri₅ being O and Rj₇ being H the most preferred. A preferred formula for the compound of the present invention is Formula Ia:

Formula Ia

wherein A is ORi, or CRiR₂R₃, wherein Rj, R₂, and R₃ are independently M, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, phosphonate, or acylthioalkyl, with or without substituents or heteroatoms; or taken together to form a cycloalkyl or aryl ring, with or without substituents or heteroatoms; for example, A is O- alkyl, O-cycloalkyl, O-aryl, C-alkyl, or 0-M, where alkyl or cycloalkyl can be also be substituted alkyl or substituted cycloalkyl; the sum of n+p is from O to 2; more preferably O;

M is H or an alkali metal; preferably M is sodium or a potassium counter ion;

X₄ is methylene or absent;

X₅ is methylene or absent;

G is oxygen, or methylene, provided when G is oxygen, X₄ and X₅ are methylene; q is 0 or 1 , provided that it is not 0 when both X₄ and X₅ are absent;

B is a purine as defined in Formula IV; preferably the purine is adenine (Ri₂ = Ri₃ = Ri₄ = H, J= carbon) having Rn as alkylamino or acylamino, more preferably acylamino; or B is a pyrimidine as defined in Formula V; preferably cytosine (Ri₆ = Rn= H) having R]₅ as alkylamino or acylamino, more preferably acylamino of Formula VI; and for both purines and pyrrolidines, the most preferred acylamino moiety is a urea or substituted urea;

Y and Z are both OH; or

Y and Z are respectively OR₄ and OR₅, where they fall under the definition of Formula III. orA preferred subset of purines of Formula Ia falls under the definition of Formula Ib:

Formula Ib

wherein A, M, X₄, G, q, Z, and Y are as previously defined in Formula Ia; and Ri ₉ is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, heterocycle, heteroaralkyl, or heteroaryl, with or without substituents.

A preferred subset of pyrimidines of the present invention falls under the definition of Formula Ic: Formula Ic

wherein A, M, X₄, G, q, Z, Y, and Ri ₉ are as previously defined in Formulae Ia and Ib. The following compounds, within the scope of the present invention, are deemed particularly useful.

Preparation of Compounds

The compounds of the present invention can be prepared according to the following general schemes, which are offered by way of illustration and not of limitation:

The first two schemes illustrate methods whereby a nucleophile (Nu) containing nucleoside residue can displace a leaving group (L) which is directly attached to an electrophilic phosphorous atom (scheme 1) or attached to an electrophilic carbon atom attached to the phosphorous atom (scheme 2). The third scheme illustrates a method whereby a nucleophilic phosphorous atom in the trivalent oxidation state displaces a suitable leaving group (L) from the 5' carbon of the ribose residue, after which the phosphorous atom is oxidized to the pentavalent oxidation state. This procedure is commonly referred to as the Arbuzov reaction, and its variants. The fourth scheme illustrates a method whereby a phosphorous ylide reacts with the 5' carbon of a ribose residue in the aldehyde oxidation state, after which the resultant double bond is reduced to the saturated analogue via standard procedures. This procedure is commonly referred to as the Wittig reaction, and its variants. The diversity of these approaches provide the chemical means to enable the compounds of the present invention.

In general Formula I, the substituents at Y and Z can be ethers, esters, acyclic acetals and ketals, carbamates, or carbonates, which are generally described by Formula II. Ethers can be prepared by reacting a hydroxyl group in a nucleoside or nucleotide with an activated form of an appropriate alkyl or aralkyl, such as an alkyl/aralkyl halide, alkyl/aralkyl sulfonate and the like, usually in the presence of an organic or inorganic base. Esters can be readily prepared by reacting a hydroxyl group in a nucleoside or nucleotide with an activated form of an appropriate organic acid, such as an acid halide or acid anyhydride in the presence of an organic or inorganic base. Alternately, use of a suitable coupling reagent such as dicyclohexylcarbodiimide, 1,1'- carbonyldiimidazole and the like to activate the organic acid can be used to achieve the same result. Acyclic acetals and ketals can be prepared by the reaction between a single hydroxyl in a nucleoside or nucleotide with aldehydes or ketones (respectively) or their chemical equivalents, under acidic conditions.

Carbamates or thiocarbamates can be most conveniently prepared by reaction of a hydroxyl group in a nucleoside or nucleotide with any of a number of commercially available isocyanates or isothiocyanates, respectively, in an inert solvent. Carbonates or thiocarbonates can be synthesized by reacting the hydroxyl groups in a nucleoside or nucleotide with an appropriate haloformate in the presence of an organic or inorganic base.

In the general Formula I, the substituents at Y and Z, when taken together, can be taken to mean acetals, ketals or orthoesters, as described by Formula III. Acetals and ketals can be readily prepared by reaction of the neighboring 2' and 3' hydroxyl groups in an appropriate nucleoside or nucleotide with an aldehyde or ketone, respectively, or their chemical equivalents, in the presence of an acid catalyst. Typical acids include trichloroacetic, p-toluenesulfonic, and methanesulfonic employed in catalytic amounts, in conjunction with inert solvents. Alternately, weaker organic acids such as formic can be used as both the catalyst and solvent for the reaction.

Cyclical orthoesters can be prepared by reaction of the neighboring 2' and 3' hydroxyl groups in a nucleoside or nucleotide with an acylic orthoester, in the presence of an acid. When the nucleoside or nucleotide to be derivatized is a purine that contains a 6- amino functionality or is a pyrimidine that contains a 4-amino functionality, it can be converted to the respective urea or thiourea, as described by general formula VI. This can be accomplished by treatment with isocyanates or isothiocyanates, respectively, as was previously described for carbamates or thiocarbamates of the 2' or 3' hydroxyls. Reactions of these amino groups with isocyanates or isothiocyanates can be carried out in the presence of the unprotected hydroxyl groups, by appropriate manipulation of the stoichiometry of the reaction.

Those skilled in the art will recognize various synthetic methodologies, which can be employed to prepare non-toxic pharmaceutically acceptable salts and acylated prodrugs of the compounds of the present invention. Methods of preparing these from the compound of

Formula I include passing an aqueous solution through a column of ion exchange resin in the desired cation form, thus converting the compound to the desired salt form. If the desired end product is a sodium salt, such as A on uridine tetraphosphate tetrasodium salt, the starting material (an ammonium or other salt) is passed through a DOW 50 H+ column to protonate the compound and generate the free acid. This protonated compound is collected in an aqueous solution of sodium hydroxide which forms the sodium salt.

As is typical for nucleotide chemistry, the reactions which give rise to compounds of the present invention usually end with several products being formed, owing to multiple reactive sites in these molecules. When multiple products are obtained, these can be separated by the use of preparative reverse phase high performance liquid chromatography (HPLC). Particularly advantageous is the use of Cl 8 or phenyl reverse phase columns, in conjunction with gradients that start with ammonium acetate buffer and end with methanol. Following chromatography, the products are isolated by evaporation of the solvent, followed by lyophilization. While separation of multiple products can be done by HPLC, another strategy is to use nucleosides or nucleotides which contain only a single functionality which is reactive under the conditions being employed. This can be accomplished by the use of protecting groups to block side reactions at other positions in the molecule. This can be done at the level of the nucleoside prior to phosphorylation and coupling of the phosphate chain with a nucleophile, or at the level of the nucleotide. Pharmaceutical Formulations

The present invention additionally provides novel pharmaceutical formulations comprising a pharmaceutically acceptable carrier and compounds of Formula I, Ia, Ib, Ic, or a pharmaceutically acceptable salt, solvate, or hydrate thereof. Pharmaceutically acceptable carriers can be selected by those skilled in the art using conventional criteria.

Pharmaceutically acceptable carriers include, but are not limited to, saline solution, aqueous electrolyte solutions, isotonicy modifiers, water polyethers such as polyethylene glycol, polyvinyls such as polyvinyl alcohol and povidone, cellulose derivatives such as methylcellulose and hydroxypropyl methylcellulose, polymers of acrylic acid such as carboxypolymethylene gel, polysaccharides such as dextrans, and glycosaminoglycans such as sodium hyaluronate and salts such as sodium chloride and potassium chloride.

The pharmaceutical formulation of the present invention provides an aqueous solution comprising water, suitable ionic or non-ionic tonicity modifiers, suitable buffering agents, and a compound of Formula I, Ia, Ib, Ic, or a pharmaceutically acceptable salt, solvate, or hydrate thereof. In one embodiment, the compound is at 0.005 to 3% w/v, and the aqueous solution has a tonicity of 200-400 mOsm/kG and a pH of 4-9.

The pharmaceutical formulation can be sterilized by filtering the formulation through a sterilizing grade filter, preferably of a 0.22-micron nominal pore size. The pharmaceutical formulation can also be sterilized by terminal sterilization using one or more sterilization techniques including but not limited to a thermal process, such as an autoclaving process, or a radiation sterilization process, or using pulsed light to produce a sterile formulation. In one embodiment, the pharmaceutical formulation is a concentrated solution of the active ingredient; the formulation can be serially diluted using appropriate acceptable sterile diluents prior to intravenous administration. hi one embodiment, the tonicity modifier is ionic such as NaCl, for example, in the amount of 0.5-0.9 % w/v, preferably 0.6-0.9 % w/v.

In another embodiment, the tonicity modifier is non-ionic, such as mannitol, dextrose, in the amount of at least 2%, or at least 2.5%, or at least 3%, and no more than 7.5%; for example, in the range of 3-5 %, preferably 3.5-5%, and more preferably 4.2-5% w/v. Those skilled in the art will recognize various synthetic methodologies that may be employed to prepare non-toxic pharmaceutically acceptable salts and prodrugs of the compounds.

Use of Mononucleoside Phosphonate Compounds

This invention provides a method of preventing or treating diseases or conditions associated with platelet aggregation and/or platelet activation. This invention also provides a method for solving treatment problems or limited treatment options caused by the aggregation of platelets or by the irreversible inhibition of platelet aggregation. This invention provides methods of preventing or treating thrombosis and related disorders, such as venous thrombosis, established peripheral arterial disease, thrombophlebitis, arterial embolism, coronary and cerebral arterial thrombosis, unstable angina, myocardial infarction, stroke, cerebral embolism, renal embolism, pulmonary embolism and other embolism- or thrombosis-related afflictions produced by but not limited to procedural or surgical interventions. This invention further provides methods for the prevention of embolism or thrombosis during percutaneous coronary interventions, placement of coronary stents, coronary angioplasty, coronary endarectomy, carotid endarectomy, or due to platelet-aggregation complications related to atherosclerosis, inflammation, exposure of blood to artificial devices, drug effects. This invention further provides methods of inhibiting platelet aggregation in blood and blood products comprising platelets, such as stored blood.

The method comprises administering to a subject or blood and blood products a composition comprising an effective amount of P2Yj₂ receptor antagonist compound, wherein said amount is effective to bind the P2Yi₂ receptors on platelets and inhibit platelet aggregation, preferably in a reversible manner.

The invention further provides useful methods of treating patients to inhibit platelet aggregation in a reversible manner, especially in patients that are subject to a procedure such as percutaneous coronary interventions, stent placement, balloon angioplasty, coronary atherectomy, coronary endarterectomy, carotid endarterectomy, thrombolytic theraphy, coronary or other vascular graft surgery, dialysis, etc. hi those patients, it is important that platelet aggregation inhibition can be rapidly reversed (within hours for oral administration and within minutes for intravenous administration) if necessary. The method comprises the steps of: (a) providing a patient in need of rapid reversal of platelet aggregation inhibition; (b) administering a therapeutically effective amount of a compound of Formula III to the patient; (c) submitting the patient to a procedure selected from the group consisting of: percutaneous coronary interventions, stent placement, balloon angioplasty, coronary atherectomy, coronary endarterectomy, carotid endarterectomy, thrombolytic theraphy, coronary or other vascular graft surgery, and dialysis, (d) discontinuing the administering of said compound to the patient; and (e) allowing the amount of said compound in the patient's blood to reduce to below an therapeutically effective amount. In step (b), the administration of the compound can be either continuous or intermittent as long as it provides a therapeutically effective amount of the compound in the patient's blood. The amount of the compound in the patient's blood is monitored.

The compounds of general Formula I, Ia, Ib, and Ic, are antagonists of the effect of ADP on its platelet membrane receptor, the P2Yj₂ receptor. The compounds of general Formula I, Ia, Ib, and Ic, are useful in therapy, in particular in the prevention or treatment of platelet aggregation. The compounds provide efficacy as antithrombotic agents by their ability to block ADP from acting at its platelet receptor site and thus prevent platelet aggregation. The compounds provide a more efficacious antithrombotic effect than aspirin, but with less profound effects on bleeding than antagonists of the fibrinogen receptor. The P2Yi₂ receptor antagonists of this invention, in contrast with currently available marketed products clopidogrel (PLA VEX®) and ticlopidine (TICLID®), bind to the P2Yj₂ receptor in a reversible fashion and therefore, the effects of the treatment with compounds described in this invention are reversed by the simple discontinuation of the treatment, restoring the hemostatic functionality of the platelet as necessary. Since platelets are non- nucleated cell particles that lack the ability to synthesize new proteins, treatment of subjects with irreversible P2Y₁₂ antagonists results in the impairment of platelet function that lasts for the lifespan of the platelet (approximately 8 to 10 days). The use of irreversible P2Yi₂ antagonists such as clopidogrel has been associated with increases in blood loss, transfusion requirements and rate of reoperation after cardiac surgery (Kapetanakis, et ah, Eur Heart J. 26: 576-83, 2005). To avoid these complications, subjects undergoing elective surgeries are required to discontinue the treatment with irreversible antagonists for at least five days prior to the surgery, which increases the risk of a thrombotic event during this period. Therefore, the compounds described in this invention represent an advantage over the currently marketed compounds.

The ADP-induced platelet aggregation is mediated by the simultaneous activation of both P2Yi₂ and P2Y_Ϊ receptors, thus the combined administration of the Formula III compounds with antagonists of platelet P2Yi receptors can provide a more efficacious antithrombotic effect at concentrations of each antagonist that are below the effective concentrations to block each receptor subtype in other systems, resulting in a decrease of the potential manifestation of adverse effects, hi addition, these compounds can be used in conjunction with lower doses of other platelet aggregation inhibitors, which work by different mechanisms, to reduce the possible side effects of said agents.

The compounds of the present invention are useful as anti -thrombotic agents, and are thus useful in the treatment or prevention of unstable angina, coronary angioplasty (PTCA) and myocardial infarction. The compounds of the present invention are useful in the treatment or prevention of primary arterial thrombotic complications of atherosclerosis such as thrombotic stroke, peripheral vascular disease, and myocardial infarction without thrombolysis.

The compounds of the invention are useful for the treatment or prevention of arterial thrombotic complications due to interventions in atherosclerotic disease such as angioplasty, endarterectomy, stent placement, coronary and other vascular graft surgery.

The compounds of the invention are useful for the treatment or prevention of thrombotic complications of surgical or mechanical damage such as tissue salvage following surgical or accidental trauma, reconstructive surgery including skin flaps, and "reductive" surgery such as breast reduction. The compounds of the present invention are useful for the prevention of mechanically- induced platelet activation in vivo, for example, caused by cardiopulmonary bypass, which results in temporary platelet dysfunction (prevention of microthromboembolism). The compounds of the present invention are useful for prevention of mechanically-induced platelet activation in vitro. For example, the compounds are useful in the preservation of blood products, e.g. platelet concentrates, prevention of shunt occlusion such as renal dialysis and plasmapheresis, and thrombosis secondary to vascular damage/inflammation such as vasculitis, arteritis, glomerulonephritis and organ graft rejection.

The compounds of the present invention are useful in disorders with a diffuse thrombotic/platelet consumption component such as disseminated intravascular coagulation, thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, heparin-induced thrombocytopenia and pre-eclampsia/eclampsia.

The compounds of the invention are useful for the treatment or prevention of venous thrombosis such as deep vein thrombosis, veno-occlusive disease, hematological conditions such as thrombocythemia and polycythemia, and migraine. The compounds of the present invention are useful in treating a mammal to alleviate the pathological effects of atherosclerosis and arteriosclerosis, acute MI, chronic stable angina, unstable angina, transient ischemic attacks and strokes, peripheral vascular disease, arterial thrombosis, preeclampsia, embolism, restenosis or abrupt closure following angioplasty, carotid endarterectomy, and anastomosis of vascular grafts. The compounds of the present invention are useful in treating chronic or acute states of hyper-aggregability, such as disseminated intravascular coagulation (DIC), septicemia, surgical or infectious shock, post-operative and post-partum trauma, cardiopulmonary bypass surgery, incompatible blood transfusion, abruptio placenta, thrombotic thrombocytopenic purpura (TTP), snake venom and immune diseases, are likely to be responsive to such treatment.

The compounds of the present invention are useful in treating diseases or conditions associated with platelet activation and/or aggregation produced by the contact of blood with an artificial device. In one embodiment, the artificial device is a paracorporeal artificial lung and an extracorporeal membrane oxigenation device. In another embodiment, the artificial device is an internal implantable artificial heart. In another embodiment, the artificial device is an apheresis instrument used to remove or isolate a specific component of the blood, and returning the remaining blood components to the donor, hi yet another embodiment, the artificial device is a hemodialysis instrument.

The compounds of the present invention are useful in vitro to inhibit the aggregation of platelets in blood and blood products, e.g. for storage, or for ex vivo manipulations such as in diagnostic or research use. In such applications, the compounds are administered to the blood or blood product.

Additionally, if the compounds of the present invention have sufficient binding affinity and bear a fluorescent moiety, they are useful as biochemical probes for the P2Y₁₂ receptor.

In a preferred embodiment, the compounds are used in the treatment of unstable angina, coronary angioplasty and myocardial infarction.

In another preferred embodiment, the compounds are useful as adjunctive therapy in the prevention or treatment of thrombotic disorders, such as coronary arterial thrombosis during the management of unstable angina, coronary angioplasty and acute myocardial infarction, for example, as adjuvants of thrombolytic therapy. The compounds are also administered in combination with other antiplatelet and/or anticoagulant drugs such as heparin, aspirin, GP Ilb/IIIa antagonists, or thrombin inhibitors.

This invention provides a method of inhibiting platelet aggregation and clot formation in a mammal, especially a human, which comprises administering to the subject a compound of Formula I, Ia, Ib, or Ic, and a pharmaceutically acceptable carrier.

This invention further provides a method for inhibiting the reocclusion of an artery or vein and the formation of new blood clots following fibrinolytic therapy, which comprises administering to a subject a compound of Formula I, Ia, Ib, or Ic, and a fibrinolytic agent. When used in the context of this invention, the term fibrinolytic agent is intended to mean any compound, whether a natural or synthetic product, which directly or indirectly causes the lysis of a fibrin clot. Plasminogen activators are a well known group of fibrinolytic agents. Useful plasminogen activators include, for example, anistreplase, urokinase (UK), pro-urokinase (pUK), streptokinase (SK), tissue plasminogen activator (tPA) and mutants, or variants thereof, which retain plasminogen activator activity, such as variants which have been chemically modified or in which one or more amino acids have been added, deleted or substituted or in which one or more functional domains have been added, deleted or altered such as by combining the active site of one plasminogen activator or fibrin binding domain of another plasminogen activator or fibrin binding molecule. The increased clinical efficacy of the combination of the compounds described in this invention with fibrinolytic agents allows the use of lower concentrations of the fibrinolytic agent, which decreases the risk of hemorrhagic events. This in turn, allows the administration of fibrinolytic therapy over an extended period of time after a heart attack or stroke.

Extracorporeal circulation is routinely used for cardiovascular surgery in order to oxygenate blood. Platelets adhere to surfaces of the extracorporeal circuit. Platelets released from artificial surfaces show impaired hemostatic function. Compounds of the invention can be administered to prevent adhesion.

Other applications of these compounds include prevention of platelet thrombosis, thromboembolism and reocclusion during and after thrombolytic therapy and prevention of platelet thrombosis, thromboembolism and reocclusion after angioplasty of coronary and other arteries and after coronary artery bypass procedures.

The active compounds can be administered systemically to target sites in a subject in need such that the extracellular concentration of a P2Yi₂ agonist is elevated to block the binding of ADP to P2Yi₂ receptor, thus inhibit the platelet aggregation. The term systemic as used herein includes subcutaneous injection, intravenous, intramuscular, intrasternal injection, intravitreal injection, infusion, inhalation, transdermal administration, oral administration, rectal administration and intra-operative instillation.

For systemic administration such as injection and infusion, the pharmaceutical formulation is prepared in a sterile medium. The active ingredient, depending on the vehicle and concentration used, can either be suspended or dissolved in the vehicle. Adjuvants such as local anesthetics, preservatives and buffering agents can also be dissolved in the vehicle. The sterile indictable preparation can be a sterile indictable solution or suspension in a nontoxic acceptable diligent or solvent. Among the acceptable vehicles and solvents that can be employed are sterile water, saline solution, or Ringer's solution.

Another method of systemic administration of the active compound involves oral administration, in which pharmaceutical compositions containing active compounds are in the form of tablets, lozenges, aqueous or oily suspensions, viscous gels, chewable gums, dispersible powders or granules, emulsion, hard or soft capsules, or syrups or elixirs.

For oral use, an aqueous suspension is prepared by addition of water to dispersible powders and granules with a dispersing or wetting agent, suspending agent one or more preservatives, and other excipients. Suspending agents include, for example, sodium carboxymethylcellulose, methylcellulose and sodium alginate. Dispersing or wetting agents include naturally-occurring phosphatides, condensation products of an allylene oxide with fatty acids, condensation products of ethylene oxide with long chain aliphatic alcohols, condensation products of ethylene oxide with partial esters from fatty acids and a hexitol, and condensation products of ethylene oxide with partial esters derived from fatty acids and hexitol anydrides. Preservatives include, for example, ethyl, and n-propyl p- hydroxybenzoate. Other excipients include sweetening agents (e.g., sucrose, saccharin), flavoring agents and coloring agents. Those skilled in the art will recognize the many specific excipients and wetting agents encompassed by the general description above.

For oral application, tablets are prepared by mixing the active compound with nontoxic pharmaceutically acceptable excipients suitable for the manufacture of tablets. These excipients can be, for example, inert diluents, such as calcium carbonate, sodium carbonate, lactose, calcium phosphate or sodium phosphate; granulating and disintegrating agents, for example, corn starch, or alginic acid; binding agents, for example, starch, gelatin or acacia; and lubricating agents, for example magnesium stearate, stearic acid or talc. The tablets can be uncoated or they can be coated by known techniques to delay disintegration and absorption in the gastrointestinal tract and thereby provide a sustained action over a longer period. For example, a time delay material such as glyceryl monostearate or glyceryl distearate can be employed. Formulations for oral use can also be presented as hard gelatin capsules wherein the active ingredient is mixed with an inert solid diluent, for example, calcium carbonate, calcium phosphate or kaolin, or as soft gelatin capsules wherein the active ingredient is mixed with water or an oil medium, for example, peanut oil, liquid paraffin or olive oil. Formulation for oral use can also be presented as chewable gums by embedding the active ingredient in gums so that the active ingredient is slowly released upon chewing. Additional means of systemic administration of the active compound to the target platelets of the subject would involve a suppository form of the active compound, such that a therapeutically effective amount of the compound reaches the target sites via systemic absorption and circulation.

For rectal administration, the compositions in the form of suppositories can be prepared by mixing the active ingredient with a suitable non-irritating excipient which is solid at ordinary temperatures but liquid at the rectal temperature and will therefore melt in the rectum to release the compound. Such excipients include cocoa butter and polyethylene glycols.

The active compounds can also be systemically administered to the platelet aggregation sites through absorption by the skin using transdermal patches or pads. The active compounds are absorbed into the bloodstream through the skin. Plasma concentration of the active compounds can be controlled by using patches containing different concentrations of active compounds.

One systemic method involves an aerosol suspension of respirable particles comprising the active compound, which the subject inhales. The active compound would be absorbed into the bloodstream via the lungs, and subsequently contact the target platelets in a pharmaceutically effective amount. The respirable particles can be liquid or solid, with a particle size sufficiently small to pass through the mouth and larynx upon inhalation; in general, particles ranging from about 1 to 10 microns, but more preferably 1-5 microns, in size are considered respirable. Another method of systemically administering the active compounds to the platelet aggregation sites of the subject involves administering a liquid/liquid suspension in the form of eye drops or eye wash or nasal drops of a liquid formulation, or a nasal spray of respirable particles that the subject inhales. Liquid pharmaceutical compositions of the active compound for producing a nasal spray or nasal or eye drops can be prepared by combining the active compound with a suitable vehicle, such as sterile pyrogen free water or sterile saline by techniques known to those skilled in the art.

Intravitreal delivery can include single or multiple intravitreal injections, or via an implantable intravitreal device that releases P2Yi₂ antagonists in a sustained capacity.

Intravitreal delivery can also include delivery during surgical manipulations as either an adjunct to the intraocular irrigation solution or applied directly to the vitreous during the surgical procedure.

For systemic administration, plasma concentrations of active compounds delivered can vary according to compounds; but are generally lxl0^~10-lxl0^~4 moles/liter, and preferably

1 x 10^"8- 1 x 10^~5 moles/liter. The pharmaceutical utility of P2Y₁₂ antagonist compounds of this invention is indicated by their inhibition of ADP-induced platelet aggregation. This widely used assay, as described in S.M.O. Hourani et at. Br. J. Pharmacol. 105, 453-457 (1992) relies on the measurement of the aggregation of a platelet suspension upon the addition of an aggregating agent such as ADP.

The invention is illustrated further by the following examples that are not to be construed as limiting the invention in scope to the specific procedures described in them.

EXAMPLES

Example 1. 2', 3'cinnamylacetal-4'-(3-phosphonato)propyl-6-N-ethylurea adenosine (compound 49)

2', 3'- cinnamylacetal-6-N-ethylurea adenosine is treated with 1,3-dicyclohexylcarbodiimide and pyridinium trifluoroacetate in DMSO to give the 5 '-oxidized analogue. This aldehyde is then dried exhaustively with the co-evaporation of toluene and dissolved in THF. Diphenyl(triphenylphosphoranylideneethyl)phosphonate is added and the reaction stirred overnight. Purification on silica gel gives the vinyl diphenyl phosphonate ester. This compound is selectively reduced with an excess of potassium azodicarboxylate in acetic acid to give the saturated diphenyl phosphonate ester compound. Removal of the phenyl ester by reaction with 1 IN NaOH gives 2',3'cinnamylacetal-4'-(3-phosphonato)propyl-6-N-ethylurea adenosine (49).

Example 2. 2', 3'- cinnamylacetal 5'-(monoethylphosphono)methyl-6-N-ethylurea adenosine (compound 37)

2', 3'- cinnamylacetal-6-N-ethylurea adenosine is dissolved in anhydrous DMF and treated with a slight excess of sodium hydride for 30 minutes. To this suspension is added a DMF solution of diethyl[(p-tolylsulfonyl)oxy]methanephosphonate. This reaction is stirred for 72 hours at ambient temperature, quenched with acetic acid, then is purified by silica gel chromatography to yield the 5'-diethylphosphono analog. This material is dissolved in anhydrous DMF and treated with one equivalent of trimethylsilyl iodide. The reaction is kept in the dark overnight, cooled and quenched by the addition of methanol. After evaporation of all solvents, the residue is purified by ion-exchange chromatography to give. 2', 3'- cinnamylacetal 5'-(monoethylphosphono)methyl-6-N-ethylurea adenosine (37).

Example 3. Platelet Aggregation Assays

Blood is collected from healthy volunteers into syringes containing 1/6 final blood volume of anti-coagulant ACD (65mM citric acid, 85mM sodium citrate, HOmM dextrose) for ished platelet (WP) preparation or into a syringe containing a final concentration of 10 units/mL heparin or 300 μM PPACK for whole blood (WB) assays. The blood collected for whole blood assays is maintained at room temperature and immediately tested as described below. The blood collected for WP is centrifuged at 18Og for 15 minutes and the supernatant (platelet rich plasma) is removed. The platelet rich plasma is centrifuged and the platelets are pelleted and resuspended in a buffer consisting of (mM): NaCl (137), KCl (2.7), CaCl₂ (2) MgCl₂ (1), NaH₂PO₄ (3), Glucose (5), HEPES (10), pH 7.4, 0.2% BSA. These centrifugations and washes are repeated twice following by resuspension in the media described above containing 0.25 U apyrase/mL. Platelet aggregation is measured using the optical mode of a ChronoLog aggregometer (Havertown, PA). Five hundred μl of platelet suspension containing 1 mg/mL Fibrinogen are warmed to 37⁰C and stirred at 1000 rpm. A maximally effective concentration of ADP (typically a concentration that produces between 90 and 100 percent of the maximal response) is added to the sample and aggregation is monitored for 8 minutes. The effects of the test compoundsare studied following the same protocol with the exception that the inhibitor is incubated for 2-5 minutes prior to the addition of a maximally effective concentration of ADP. For whole blood aggregation, blood is diluted 1 : 1 with saline and then aggregation is performed in the same manner as described above using the impedance mode of the aggregometer.

The potency of agonists and inhibitors of platelet aggregation is calculated from both, the rate of aggregation and the maximal extent of aggregation obtained for each determination by fitting the data to a four-parameter logistic equation using the GraphPad software package (GraphPad Corp. San Diego, CA). The ability of Formula I compound to inhibit platelet aggregation is presented as IC₅₀, the IC_5O values represent the concentration of antagonist needed to inhibit by 50% the aggregation elicited by a given concentration of ADP.

Although the invention has been described with reference to the presently preferred embodiments, it should be understood that various modifications could be made without departing from the scope of the invention.

Claims

WHAT IS CLAIMED:

1. A compound of Formula Ia, or a tautomer, a salt, a solvate, a hydrate thereof:

Formula Ia

wherein

A is ORi, or CRiR₂R₃, wherein Ri, R₂, and R₃ are independently M, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, phosphonate, or acylthioalkyl, with or without substituents or heteroatoms; or taken together to form a cycloalkyl or aryl ring, with or without substituents or heteroatoms; the sum of n+p is from O to 2; M is H or an alkali metal;

X₄ and X₅ are independently methylene or absent;

G is oxygen, or methylene, provided when G is oxygen, X₄ and X₅ are methylene; q is O or 1 , provided that when both X₄ and X₅ are absent, q is not O; B is a purine as defined by Formula IV, or a pyrimidine as defined by Formula V;

Y and Z are both OH; or

Y and Z are respectively OR₄ and OR₅, where they fall under the definition of Formula III;

Formula IV

wherein: Rn and R]₅ are hydroxy, oxo, amino, mercapto, alkylthio, arylthio, alkyloxy, aryloxy, alkylamino, cycloalkylamino, aralkylamino, arylamino, diaralkylamino, diarylamino, or dialkylamino, where the alkyl groups are optionally linked to form a heterocycle; or

Rn and Ri₅ are acylamino; or

J is carbon or nitrogen, provided that when J is nitrogen, R₁₃ is not present; Ri₂ is hydrogen, O or is absent;

Ri ₆ is hydrogen, acyl, or absent;

Ri₃ is hydrogen, alkyl, bromo, azido, alkylamino, arylamino or aralkylamino, alkoxy, aryloxy or aralkyloxy, alkylthio, arythio or aralkylthio, or CO-E(C_1-6 alkyl)G-, wherein E and G are independently amino, mercapto, hydroxy or carboxyl; Rj₄ is hydrogen, halo, amino, monosubstituted amino, disubstituted amino, alkylthio, arylthio, or aralkylthio, where the substituent on sulfur contains up to a maximum of 20 carbon atoms, with or without unsaturation;

Rn is hydrogen, halo, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, with or without substitution;

Formula III

wherein O is the 2' and 3' oxygens of the furanose or carbocycle; and the 2' and 3' oxygens of the furanose or carbocycle are linked by a common carbon atom to form a cyclical acetal, cyclical ketal, or cyclical orthoester; for cyclical acetals and ketals, R₉ and Rio are independently H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, with or without substitution; or can be joined together to form a homocyclic or heterocyclic ring composed of 3 to 8 atoms; for cyclical orthoesters, R₉ is H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, with or without substitution; and R_1O is alkyloxy, cycloalkyloxy, aralkyloxy, aryloxy, with or without substitution.

2. The compound according to Claim 1, wherein Rn and Rj₅ are independently an acylamino as defined by Formula VI:

Formula VI

wherein:

NH is the amino residue at the C-6 position in a purine or the amino residue at the C-4 position in a pyrimidine;

W is oxygen or sulfur; Ri ₈ is amino or mono- or disubstituted amino such that the moiety according to Formula VI is a urea or thiourea; or

Ri ₈ is alkoxy, aralkyloxy, aryloxy, substituted aralkyloxy, or substituted aryloxy, such that the moiety according to Formula VI is a carbamate or thiocarbamate; or

Ri ₈ is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, with or without substitution, with or without heteroatoms, such that the moiety according to Formula VI is an amide.

3. The compound according to Claim 2, wherein W= O, and R]₈ is amino, or mono- or disubstituted amino such that the acylamino is a urea.

4. The compound according to Claim 2, wherein B is a purine as defined by Formula IV, Rn = absent, R₁₃ = R₁₄ = H, and J= carbon.

5. The compound according to Claim 2, wherein B is a pyrimidine as defined by Formula V, Ri₆ = absent, and Rn = H.

6. The compound according to Claim 1 , wherein said compound is defined by Formula Ib:

Formula Ib

wherein A, M, X₄, G, q, Z, and Y are as defined in Claim 1 ; and

Ri₉ is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, heterocycle, heteroaralkyl, or heteroaryl, with or without substituents.

7. The compound according to Claim 1 , wherein said compound is defined by Formula Ic:

Formula Ic

wherein A, M, X₄, G, q, Z, and Y are as defined in Claim 1 ; and

R₁₉ is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, heterocycle, heteroaralkyl, or heteroaryl, with or without substituents.

8. A method of preventing or treating diseases or conditions associated with platelet aggregation comprising: administering to a subject a therapeutically effective amount of the compound according to any one of Claims 1-7, wherein said amount is effective to inhibit platelet aggregation.

9. The method according to Claim 8, wherein said compound reversibly inhibits

ADP-induced platelet aggregation.

10. The method according to Claim 8, wherein said compound is administered in combination with an antiplatelet and/or anticoagulant drug.

11. The method according to Claim 8, wherein said diseases associated with platelet aggregation are disorders characterized by thrombosis, primary arterial thrombotic complications of atherosclerotic disease, thrombosis secondary to vascular damage and inflammation, indications with a diffuse thrombotic or platelet consumption component, venous thrombosis, coronary arterial thrombosis, pathological effects of atherosclerosis and arteriosclerosis, chronic or acute states of platelet hyper-aggregability, reocclusion of an artery or vein following fibrinolytic therapy.

12. The method according to Claim 11 , wherein said thrombosis are unstable angina, or myocardial infarction; said primary arterial thrombotic complications of atherosclerosis are thrombotic stroke, peripheral vascular disease, or myocardial infarction; said thromboses secondary to vascular damage and inflammation are vasculitis, arteritis, glomerulonephritis or organ graft rejection; said indications with a diffuse thrombotic or platelet consumption component are disseminated intravascular coagulation, thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, heparin-induced thrombocytopenia, pre-eclampsia, or eclampsia; said venous thrombosis are deep vein thrombosis, veno- occlusive disease, or hematological conditions; and said coronary arterial thrombosis is associated with unstable angina, coronary angioplasty or acute myocardial infarction.

13. The method according to Claim 11, wherein said pathological effects of atherosclerosis and arteriosclerosis are arteriosclerosis, acute myocardial infarction, chronic stable angina, unstable angina, transient ischemic attacks, strokes, peripheral vascular disease, arterial thrombosis, pre-eclampsia, embolism, restenosis or abrupt closure following angioplasty, carotid endarterectomy, or anastomosis of vascular grafts; said chronic or acute states of hyper-aggregability is caused by DIC, septicemia, surgical or infectious shock, postoperative trauma, post-partum trauma, thrombotic thrombocytopenic purpura, snake venom or immune diseases.

14. The method according to Claim 8, wherein said conditions are associated with procedures resulting in platelet aggregation, said conditions are selected from the group consisting of thrombotic complications of interventions to treat atherosclerotic disease, thrombotic complications resulting from surgical procedures, thrombotic complications resulting from mechanically-induced platelet activation, shunt occlusion, thrombosis secondary to vascular damage and inflammation, platelet adhesion associated with extracorporeal circulation, platelet activation associated with extracorporeal circulation, thrombotic complications associated with thrombolytic therapy, thrombotic complications associated with coronary and other angioplasty, and thrombotic complications associated with coronary artery bypass procedures.

15. The method according to Claim 14, wherein said thrombotic complications of interventions to treat atherosclerotic disease are associated with procedures of angioplasty, endartectomy, or stent placement; said surgical procedures are coronary revascularization procedures, vascular graft surgery, tissue salvage following surgical or accidental trauma, or reconstructive surgery; said mechanical-induced platelet activation is caused by cardiopulmonary bypass resulting in microthromboembolism, platelet refractoriness, and thrombocytopenia; said thrombotic complications resulting from shunt occlusion are associated with procedures of renal dialysis or plasmapheresis.

16. The method according to Claim 8, wherein said conditions associated with platelet aggregation are produced by the contact of blood with an artificial device.

17. The method according to Claim 16, wherein said artificial device is a hemodialysis instrument, a paracorporeal artificial lung and an extracorporeal membrane oxygenation device, an internal implantable artificial heart, an apheresis instrument used to remove or isolate a specific component of the blood and returning the remaining blood components to a donor.

18. The method according to Claim 8, wherein said administering is oral administration of said compound to a subject.

19. A method for in vitro inhibiting the aggregation of platelets in blood or blood product, comprising the step of administerting to the blood or blood product the compound according to any one of Claims 1-7.