HK1014668B - Bicyclic fibrinogen antagonists - Google Patents

Description

Field of the Invention

This invention relates to novel bicyclic compounds which inhibit platelet aggregation, pharmaceutical compositions containing the compounds and methods of using the compounds.

Background of the Invention

Platelet aggregation is believed to be mediated primarily through the fibrinogen receptor, or GPIIb-IIIa platelet receptor complex, which is a member of a family of adhesion receptors referred to as integrins. It has been found that frequently the natural ligands of integrin receptors are proteins which contain an Arg-Gly-Asp sequence. Von Willebrand factor and fibrinogen, which are considered to be natural ligands for the GPIIb-IIIa receptor, possess an Arg-Gly-Asp (RGD in single letter amino acid code) sequence in their primary structure. Functionally, these proteins are able to bind and crosslink GPIIb-IIIa receptors on adjacent platelets and thereby effect aggregation of platelets.

Fibronectin, vitronectin and thrombospondin are RGD-containing proteins which have also been demonstrated to bind to GPIIb-IIIa. Fibronectin is found in plasma and as a structural protein in the intracellular matrix. Binding between the structural proteins and GPIIb-IIIa may function to cause platelets to adhere to damaged vessel walls.

Linear and cyclic peptides which bind to vitronectin and contain an RGD sequence are disclosed in WO 89/05150 (PCT US88/04403). EP 0 275 748 discloses linear tetra- to hexapeptides and cyclic hexa- to octapeptides which bind to the GPIIb-IIIa receptor and inhibit platelet aggregation. Other linear and cyclic peptides, the disclosure of which are incorporated herein by reference, are reported in EP-A 0 341 915. However, the peptide like structures of such inhibitors often pose problems, such as in drug delivery, metabolic stability and selectivity. Inhibitors of the fibrinogen receptor which are not constructed of natural amino acid sequences are disclosed in EP-A 0 372,486, EP-A 0 381 033 and EP-A 0 478 363. WO 92/07568 (PCT/US91/08166) discloses fibrinogen receptor antagonists which mimic a conformational γ-turn in the RGD sequence by forming a monocyclic seven-membered ring structure. There remains a need, however, for novel fibrinogen receptor antagonists (e.g. inhibitors of the GPIIb-IIIa protein) which have potent in vivo and in vitro effects and lack the peptide backbone structure of amino acid sequences.

The present invention discloses novel bicyclic benzodiazepine compounds, which are inhibitors of the GPIIb-IIIa receptor and inhibit platelet aggregation. Certain 5-phenyl-1,4-benzodiazepines are known as a class of drugs which affect the central nervous system, and have been used as anxiolytics. See Stembach, L.H., J. Med. Chem., 22, 2 (1979). It has also been disclosed that certain 5-phenyl-1,4-benzodiazepines antagonize the effects of cholecystokinin. See Friedinger, Med. Res. Rev., 9, 271 (1989). Certain bicyclic compounds which have fibrinogen antagonist activity are disclosed in WO 93/08174 (PCT/US92/08788), WO 93/00095 (PCT/US/92/05463) and WO 94/14776 (PCT/US93/12436).

Summary of the Invention

In one aspect this invention is a compound as hereinafter disclosed for inhibiting platelet aggregation.

This invention is also a pharmaceutical composition for inhibiting platelet aggregation or clot formation, which comprises a compound of the invention and a pharmaceutically acceptable carrier.

This invention further comprises the use of a compound as hereinafter described in the manufacture of a medicament for inhibiting platelet aggregation

In another aspect, this invention provides a method for inhibiting reocclusion of an artery or vein in a mammal following fibrinolytic therapy or angioplasty, which comprises internally administering an effective amount of a compound of the invention. This invention is also a method for treating stroke, transient ischemia attacks, or myocardial infarction.

Detailed Description of the Invention

Although not intending to be bound to any specific mechanism of action, the compounds of this invention are believed to inhibit the binding of fibrinogen to the platelet-bound fibrinogen receptor GPIIb-IIIa, and may interact with other adhesion proteins via antagonism of a putative RGD binding site.

Compounds of this invention are encompassed by a compound which is (R,S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid; or (S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid or a pharmaceutically acceptable salt thereof.

Abbreviations and symbols commonly used in the peptide and chemical arts are used herein to describe the compounds of this invention. In general, the amino acid abbreviations follow the IUPAC-IUB Joint Commission on Biochemical Nomenclature as described in Eur. J. Biochem., 158, 9 (1984).

t-Bu refers to the tertiary butyl radical, Boc refers to the t-butyloxycarbonyl radical, Fmoc refers to the fluorenylmethoxycarbonyl radical, Ph refers to the phenyl radical, Cbz refers to the benzyloxycarbonyl radical, BrZ refers to the o-bromobenzyloxycarbonyl radical, C1Z refers to the o-chlorobenzyloxycarbonyl radical, Bzl refers to the benzyl radical, 4-MBzl refers to the 4-methyl benzyl radical, Me refers to methyl, Et refers to ethyl, Ac refers to acetyl, Alk refers to C_1-4alkyl, Nph refers to 1- or 2-naphthyl and cHex refers to cyclohexyl.

DCC refers to dicyclohexylcarbodiimide, DMAP refers to 4-(dimethylamino) pyridine, DIEA refers to diisopropylethyl amine, EDC refers to N-ethyl-N'-(dimethylaminopropyl)-carbodiimide.HOBt refers to 1-hydroxybenzotriazole, THF refers to tetrahydrofuran, DMF refers to dimethyl formamide, NBS refers to N-bromosuccinimide, Pd/C refers to a palladium on carbon catalyst, PPA refers to 1-propanephosphonic acid cyclic anhydride, DPPA refers to diphenylphosphoryl azide, BOP refers to benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate, HF refers to hydrofluoric acid, TEA refers to triethylamine, TFA refers to trifluoroacetic acid, PCC refers to pyridinium chlorochromate.

Compounds of this invention are prepared by treating, in any order, a compound of the structure: wherein A¹ is NH, X is H, R is H or a carboxy protecting group, R₃ is methyl and R^6' is 7-(4,4'-bipiperidin-1-yl)carbonyl wherein the basic nitrogen is protected, with a reagent, in any order:

• (i) to remove an amino protecting group from R6'; and, if necessary,
• (ii) to remove a carboxy protecting group from CO2R; and
• (iii) form a pharmaceutically acceptable salt thereof.

Illustrative of R^6' is R⁶ wherein the piperidinyl group is protected by a benzyloxy, t-butoxycarbonyl or trifluoroacetyl group.

The compounds of formula (IV) are generally prepared by reacting a compound of the formula (XI) with a compound of the formula (XII):         R^6"-L²     (XII) wherein A¹ is NH and R³ is methyl, with any reactive functional groups protected, R is H or a carboxy protecting group, L¹ is CO₂H.

L¹ and L² are functional groups which are capable of reacting to form an amide bond. L² is a basic nitrogen group, such as the nitrogen of a piperidinyl group. For instance R^6"-L² is 4-(4-piperidinyl)piperidine, wherein the non-reactive basic nitrogen of the piperidinyl group is protected by an amino protecting group.

The compounds of formula (XI) are benzodiazepines and are prepared by general methods known in the art such as those disclosed in WO 93/00095 (PCT/US/92/05463) and WO 94/14776 (PCT/US93/12436) which are incorporated herein by reference. Compounds of formula (XII) generally contain two basic centers of which one is protected, and are likewise known to the art. See, for instance, WO94/14776.

Coupling reagents as used herein denote reagents which may be used to form amide bonds. Typical coupling methods employ carbodiimides, activated anhydrides and esters, and acyl halides. Reagents such as EDC, DCC, DPPA, PPA, BOP reagent, HOBt, N-hydroxysuccinimide and oxalyl chloride are typical.

Coupling methods to form amide bonds are generally well known to the art. The methods of peptide synthesis generally set forth by Bodansky et al., THE PRACTICE OF PEPTIDE SYNTHESIS, Springer-Verlag, Berlin, 1984, Ali et al. in J. Med. Chem., 29, 984 (1986) and J. Med. Chem., 30, 2291 (1987) are generally illustrative of the technique and are incorporated herein by reference.

Solution synthesis for the formation of amide bonds is accomplished using conventional methods used to form amide bonds. Typically, the amine or aniline is coupled via its free amino group to an appropriate carboxylic acid substrate using a suitable carbodiimide coupling agent, such as N,N'-dicyclohexyl carbodiimide (DCC) or EDC, optionally in the presence of catalysts such as 1-hydroxybenzotriazole (HOBt) and dimethylamino pyridine (DMAP). Other methods, such as the formation of activated esters, anhydrides or acid halides, of the free carboxyl of a suitably protected acid substrate, and subsequent reaction with the free amine of a suitably protected amine, optionally in the presence of a base, are also suitable. For example, a protected Boc-amino acid or Cbz-amidino benzoic acid is treated in an anhydrous solvent, such as methylene chloride or tetrahydrofuran (THF), in the presence of a base, such as N-methyl morpholine, DMAP or a trialkylamine, with isobutyl chloroformate to form the "activated anhydride", which is subsequently reacted with the free amine of a second protected amino acid or aniline.

The reactive functional groups of the sidechains of each synthetic fragment are suitably protected as known in the art. Suitable protective groups are disclosed in Greene, PROTECTIVE GROUPS IN ORGANIC CHEMISTRY, John Wiley and Sons, New York, 1981. For example, the Boc, Cbz, phthaloyl or Fmoc group may be used for protection of an amino (or the nitrogen of a piperidinyl) or amidino group. The Boc group is generally preferred for protection of an amino group. A methyl, ethyl, t-Bu, cHex, benzyl, substituted benzyl, (pivaloyl)methyl or (2-methyl-2-methoxypropanoyl)methyl ester may be used for the protection of the carboxyl group. A benzyl group or suitably substituted benzyl group (e.g., 4-methoxy-benzyl or 2,4-dimethoxy-benzyl) is used to protect the mercapto group or the hydroxyl group. The tosyl group may be used for protection of the imidazolyl group and tosyl or nitro group for protection of the guanidino group. A suitably substituted carbobenzyloxy group or benzyl group may also be used for the hydroxyl group or amino group. Suitable substitution of the carbobenzyloxy or benzyl protecting groups is ortho and/or para substitution with chloro, bromo, nitro, methoxy or methyl, and is used to modify the reactivity of the protective group. Except for the Boc group, the protective groups for the amino moiety are, most conveniently, those which are not removed by mild acid treatment. These protective groups are removed by such methods as catalytic hydrogenation, sodium in liquid ammonia or HF treatment, as known in the art.

Methods for removal of the α carboxy or amino protecting group are well known in the art. For example, an alkyl or cycloalkyl ester may be removed by basic hydrolysis, for instance an alkali metal hydroxide, such as sodium, potassium or lithium hydroxide in a suitable solvent, such as aqueous alcohol. A benzyl ester is typically removed by hydrogenation over a palladium catalyst. A basic nitrogen protected by a t-butyloxycarbonyl group, or a t-butyl ester, is typically removed by acid treatment, such as by trifluoroacetic acid or hydrochloric acid, optionally diluted with a solvent, such as methylene chloride and/or dioxane. The benzyloxycarbonyl group is generally removed by hydrogenation over a palladium catalyst. A trifluoroacetyl group is typically removed by basic hydrolysis, such as by treatment with an alkali metal hydroxide in a suitable solvent. One useful synthetic method for protecting the basic nitrogen of a piperidinyl group is to carry the group through a synthesis as a pyridinyl group, which may be reduced with a platinum catalyst toward the end of the synthesis to "remove" the protecting group.

Acid addition salts of the compounds are prepared in a standard manner in a suitable solvent from the parent compound and an excess of an acid, such as hydrochloric, hydrobromic, sulfuric, phosphoric, acetic, maleic, succinic or methanesulfonic. Most of the compounds form inner salts or zwitterions which may be acceptable. Cationic salts are prepared by treating the parent compound with an excess of an alkaline reagent, such as a hydroxide, carbonate or alkoxide, containing the appropriate cation; or with an appropriate organic amine. Cations such as Li+, Na+, K+, Ca++, Mg++ and NH₄+ are specific examples of cations present in pharmaceutically acceptable salts.

This invention provides a pharmaceutical composition which comprises a compound according to this invention and a pharmaceutically acceptable carrier. Accordingly, the compounds of this invention may be used in the manufacture of a medicament. Pharmaceutical compositions of the compounds of this invention prepared as hereinbefore described may be formulated as solutions or lyophilized powders for parenteral administration. Powders may be reconstituted by addition of a suitable diluent or other pharmaceutically acceptable carrier prior to use. The liquid formulation may be a buffered, isotonic, aqueous solution. Examples of suitable diluents are normal isotonic saline solution, standard 5% dextrose in water or buffered sodium or ammonium acetate solution. Such formulation is especially suitable for parenteral administration, but may also be used for oral administration or contained in a metered dose inhaler or nebulizer for insufflation. It may be desirable to add excipients such as polyvinylpyrrolidone, gelatin, hydroxy cellulose, acacia, polyethylene glycol, mannitol, sodium chloride or sodium citrate.

Alternately, these compounds may be encapsulated, tableted or prepared in a emulsion or syrup for oral administration. Pharmaceutically acceptable solid or liquid carriers may be added to enhance or stabilize the composition, or to facilitate preparation of the composition. Solid carriers include starch, lactose, calcium sulfate dihydrate, terra alba, magnesium stearate or stearic acid, talc, pectin, acacia, agar or gelatin. Liquid carriers include syrup, peanut oil, olive oil, saline and water. The carrier may also include a sustained release material such as glyceryl monostearate or glyceryl distearate, alone or with a wax. The amount of solid carrier varies but, preferably, will be between about 20 mg to about 1 g per dosage unit. The pharmaceutical preparations are made following the conventional techniques of pharmacy involving milling, mixing, granulating, and compressing, when necessary, for tablet forms; or milling, mixing and filling for hard gelatin capsule forms. When a liquid carrier is used, the preparation will be in the form of a syrup, elixir, emulsion or an aqueous or non-aqueous suspension. Such a liquid formulation may be administered directly p.o. or filled into a soft gelatin capsule.

For rectal administration, the compounds of this invention may also be combined with excipients such as cocoa butter, glycerin, gelatin or polyethylene glycols and molded into a suppository.

The compounds of this invention may be used 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, therapeutic or research use.

A method of inhibiting platelet aggregation and clot formation in a mammal, especially a human comprises the internal administration of a compound of this invention and a pharmaceutically acceptable carrier. Indications for such therapy include acute myocardial infarction (AMI), deep vein thrombosis, pulmonary embolism, dissecting anurysm, transient ischemia attack (TIA), stroke and other infarct-related disorders, and unstable angina. The compounds of this invention are also useful for preventing restenosis of an artery or vein in a mammal following angioplasty. 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. These compounds are also believed to be useful for adjunct therapy following angioplasty. In addition, the compounds of this invention may be useful in a method for the prevention of metastatic conditions, the prevention or treatment of fungal or bacterial infection, inducing immunostimulation, treatment of sickle cell disease, and the prevention or treatment of diseases in which bone resorption is a factor, such as osteoporosis.

The compounds of this invention may also be favorably administered with other agents which inhibit platelet aggregation. For instance, the compounds of this invention may be administered with compounds of the class of cyclooxygenase inhibitors, thromboxane antagonists, thromboxane synthetase inhibitors, heparins, thrombin inhibitors, ADP receptor inhibitors/antagonists and ticlopidine. Examples of such agents are aspirin, warfarin and clopidogrel.

The compound is administered either orally or parenterally to the patient, in a manner such that the concentration of drug in the plasma is sufficient to inhibit platelet aggregation, or other such indication. The pharmaceutical composition containing the compound is administered at a dose between about 0.2 to about 50 mg/kg in a manner consistent with the condition of the patient. For acute therapy, parenteral administration is preferred. For persistent states of hyperaggregability, an intravenous infusion of the compound in 5% dextrose in water or normal saline is most effective, although an intramuscular bolus injection may be sufficient.

For chronic, but noncritical, states of platelet aggregability, oral administration of a capsule or tablet, or a bolus intramuscular injection is suitable. The compound is administered one to four times daily at a level of about 0.4 to about 50 mg/kg to achieve a total daily dose of about 0.4 to about 200 mg/kg/day.

A method for inhibiting the reocclusion or restenosis of an artery or vein following fibrinolytic therapy comprises internal administration of a compound of this invention and a fibrinolytic agent. It has been found that administration of a compound in fibrinolytic therapy either prevents reocclusion completely or prolongs the time to reocclusion.

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 or functional domains have been added, deleted or altered such as by combining the active site of one plasminogen activator with the fibrin binding domain of another plasminogen activator or fibrin binding molecule. Other illustrative variants include tPA molecules in which one or more glycosylation sites have been altered. Preferred among plasminogen activators are variants of tPA in which the primary amino acid sequence has been altered in the growth factor domain so as to increase the serum half-life of the plasminogen activator. tPA Growth factor variants are disclosed, e.g., by Robinson et al., EP-A 0 297 589 and Browne et al., EP-A 0 240 334. Other variants include hybrid proteins, such as those disclosed in EP 0 028 489, EP 0 155 387 and EP 0 297 882, all of which are incorporated herein by reference. Anistreplase is a preferred hybrid protein for use in this invention. Fibrinolytic agents may be isolated from natural sources, but are commonly produced by traditional methods of genetic engineering.

Useful formulations of tPA, SK, UK and pUK are disclosed, for example, in EP-A 0 211 592, EP-A 0 092 182 and U.S. Patent 4,568,543, all of which are incorporated herein by reference. Typically the fibrinolytic agent may be formulated in an aqueous, buffered, isotonic solution, such as sodium or ammonium acetate or adipate buffered at pH 3.5 to 5.5. Additional excipients such as polyvinyl pyrrolidone, gelatin, hydroxy cellulose, acacia, polyethylene, glycol, mannitol and sodium chloride may also be added. Such a composition can be lyophilized.

The pharmaceutical composition may be formulated with both the compound of this invention and fibrinolytic in the same container, but formulation in different containers is preferred. When both agents are provided in solution form they can be contained in an infusion/injection system for simultaneous administration or in a tandem arrangement.

Indications for such therapy include myocardial infarction, deep vein thrombosis, pulmonary embolism, stroke and other infarct-related disorders. The compound is administered just prior to, at the same time as, or just after parenteral administration of tPA or other fibrinolytic agent. It may prove desirable to continue treatment with the compound for a period of time well after reperfusion has been established to maximally inhibit post-therapy reocclusion. The effective dose of tPA, SK, UK or pUK may be from 0.5 to 5 mg/kg and the effective dose of the compound may be from about 0.1 to 25 mg/kg.

For convenient administration of the inhibitor and the fibrinolytic agent at the same or different times, a kit is prepared, comprising, in a single container, such as a box, carton or other container, individual bottles, bags, vials or other containers each having an effective amount of the inhibitor for parenteral administration, as described above, and an effective amount of tPA, or other fibrinolytic agent, for parenteral administration, as described above. Such kit can comprise, for example, both pharmaceutical agents in separate containers or the same container, optionally as lyophilized plugs, and containers of solutions for reconstitution. A variation of this is to include the solution for reconstitution and the lyophilized plug in two chambers of a single container, which can be caused to admix prior to use. With such an arrangement, the fibrinolytic and the compound may be packaged separately, as in two containers, or lyophilized together as a powder and provided in a single container. When both agents are provided in solution form, they can be contained in an infusion/injection system for simultaneous administration or in a tandem arrangement. For example, the platelet aggregation inhibitor may be in an i.v. injectable form, or infusion bag linked in series, via tubing, to the fibrinolytic agent in a second infusion bag. Using such a system, a patient can receive an initial bolus-type injection or infusion, of the inhibitor followed by an infusion of the fibrinolytic agent.

The pharmacological activity of the compounds of this invention is assessed by their ability to inhibit the binding of ³H-SK&F 107260, a known RGD-fibrinogen antagonist, to the GPIIbIIIa receptor; their ability to inhibit platelet aggregation, in vitro, and their ability to inhibit thrombus formation in vivo.

Inhibition of RGD-mediated GPIIb-IIIa binding

Inhibition of RGD-mediated GPIIb-IIIa binding was demonstrated by assessing the ability of compounds to inhibit the binding of ³H-SK&F 107260, a known RGD-fibrinogen antagonist, to the GPIIbIIIa receptor according to the procedure disclosed in WO 93/00095 (PCT/US/92/05463).

Inhibition of Platelet Aggregation

Inhibition of platelet aggregation was demonstrated following the procedure disclosed in WO 93/00095 (PCT/US/92/05463).

The compounds of this invention generally inhibit the aggregation of human platelets stimulated with ADP with IC50 of less than 0.1 µM. The compound of Example 3 has IC50 of between 0.2 and 11 µM.

To assess the stability of the compounds to plasma proteases, the compounds were incubated for 3 h (rather than 3 min) in the PRP prior to addition of the agonist.

In Vivo Inhibition of Platelet Aggregation

In vivo inhibition of thrombus formation is demonstrated by recording the systemic and hemodynamic effects of infusion of the compounds into anesthetized dogs according to the methods described in Aiken et al., Prostaglandins, 19, 629 (1980). Alternately, inhibition of thrombus formation and bioavailability may be measured by the method disclosed by Nichols et al., J. Pharmacol. Exp. Ther., 270, 614 (1994).

The examples which follow are intended to in no way limit the scope of this invention, but are provided to illustrate how to make and use the compounds of this invention. Many other embodiments will be readily apparent and available to those skilled in the art.

EXAMPLES

In the Examples, all temperatures are in degrees Centigrade. Mass spectra were performed using fast atom bombardment (FAB) or electro-spray (ES) ionization. Melting points were taken on a Thomas-Hoover capillary melting point apparatus and are uncorrected.

NMR were recorded at 250 MHz using a Bruker AM 250 spectrometer, unless otherwise indicated. Chemical shifts are reported in ppm (δ) downfield from tetramethylsilane. Multiplicities for NMR spectra are indicated as: s=singlet, d=doublet, t=triplet, q=quartet, m=multiplet, dd=doublet of doublets, dt=doublet of triplets etc. and br indicates a broad signal. J indicates the NMR coupling constant in Hertz.

Celite® is filter aid composed of acid washed diatomaceous silica, and is a registered trademark of Mansville Corp., Denver, Colorado. Florisil® is an activated magnesium silicate chromatographic support and is a registered trademark of Floridon Co., Pittsburgh, Pennsylvania. Analtech silica gel GF and EM silica gel thin layer plates were used for thin layer chromatography. Both flash and gravity chromatography were carried out on Merck 60 (230-400 mesh) silica gel. ODS refers to an octadecylsilyl derivatized silica gel chromatographic support. AN/W-TFA indicates an isocratic eluant system of the indicated percentage of acetonitrile in water with 0.1% TFA. 5µ Apex-ODS indicates an octadecylsilane derivatized silica gel support, having a nominal particle size of 5µ, made by Jones Chromatography, Littleton, Colorado. YMC ODS-AQ® is an ODS chromatographic support and is a registered trademark of YMC Co. Ltd., Kyoto, Japan. PRP-1® is a polymeric (styrene-divinyl benzene) chromatographic support and is a registered trademark of Hamilton Co., Reno, Nevada.

Preparation 1 Preparation of (R,S)-7-[[[4-(aminoiminomethyl)phenyl]-methylamino]carbonyl]-2,3,4,5-tetrahydro-3-oxo-2-(2-phenylethyl)-1H-2-benzazepine-4-acetic acid a) t-butyl 3-bromo-4-methylbenzoate

Dimethylformamide dimethyl acetal (48 mL, 200 mmol) was added dropwise over 15 min to a suspension of 3-bromo-4-methylbenzoic acid (85%; 10.75 g, 42.5 mmol) in toluene (100 mL) at 70°C. The reaction was stirred at 70-80°C for an additional 0.5 h, then was cooled, washed sequentially with water and 5% sodium bicarbonate, and dried (sodium sulfate). The mixture was filtered through a pad of silica gel, and the filter pad was washed with toluene. The filtrate was concentrated to afford the title compound (8.0 g, 69%) as a yellow oil. TLC (toluene) R_f 0.68.

b) t-butyl 3-bromo-4-(bromomethyl)benzoate

A mixture of the compound of Preparation 1 (a) (1.36 g, 5 mmol), N-bromosuccinimide (0.98 g, 5.5 mmol), and benzoyl peroxide (61 mg, 0.25 mmol) in carbon tetrachloride (25 mL) was heated at reflux. After 4 h, the mixture was cooled and filtered, and the filtrate was concentrated. The resulting material was used without purification. TLC R_f 0.39 (5:95 ethyl acetate:hexane).

c) t-butyl 3-bromo-4-[[(2-phenylethyl)amino]methyl]-benzoate

The compound of Preparation 1 (b) was dissolved in dry ether (25 mL), and phenethylamine (1.9 mL, 15 mmol) was added. The addition was slightly exothermic, and the reaction became cloudy. The reaction was stirred at RT overnight, then was diluted with ether (75 mL) and was washed sequentially with 5% sodium bicarbonate and brine (25 mL). Drying (MgSO₄), concentration, and silica gel chromatography (33% ethyl acetate/hexane) gave the title compound (1.26 g, 65%) as a pale yellow oil. TLC Rf 0.42 (30:70 ethyl acetate:hexane).

d) t-butyl 3-bromo-4-[[[N-(2-phenylethyl)-N-t-butoxycarbonyl]amino]methyl]benzoate

Di-t-butyl dicarbonate (845 mg, 3.88 mmol) was added all at once to a solution of the compound of Preparation 1(c) (1.26 g, 3.23 mmol) in chloroform (16 mL) at RT. The reaction was stirred at RT for 1.5 h, then at reflux for 0.5 h. Concentration and chromatography (silica gel, 10% ethyl acetate/hexane) gave the title compound (1.57 g, 99%) as a colorless oil which solidified in vacuo. TLC Rf 0.49(10:90 ethyl acetate:hexane).

e) methyl 3-methoxycarbonyl-4-[[5-(t-butoxycarbonyl)-2-[[N-(2-phenylethyl)-N-t-(butoxycarbonyl)]amino]methyl]-phenyl]-2-butenoate and methyl 3-methoxycarbonyl-4-[[5-(t-butoxycarbonyl)-2-[[N-(2-phenylethyl)-N-t-butoxycarbonyl)]amino]methyl]phenyl]-3-butenoate.

A mixture of the compound of Preparation 1 (d) (1.34 g, 2.73 mmol), dimethyl itaconate (648 mg, 4.10 mmol), palladium (II) acetate (30.7 mg, 0.14 mmol), tri-o-tolylphosphine (83.2 mg, 0.27 mmol), dry triethylamine (0.76 mL, 5.46 mmol), and dry acetonitrile (27 mL) was deoxygenated through a single evacuation/argon purge cycle, then was heated at reflux under argon. After 6 h, the reaction was cooled, and more palladium (II) acetate (30.7 mg, 0.14 mmol) and tri-o-tolylphosphine (83.2 mg, 0.27 mmol) were added. The mixture was deoxygenated through three evacuation/argon purge cycles, then was heated at reflux under argon overnight (16.5 h). The reaction was concentrated, and the residue was dissolved in ether and washed with water and brine. Drying (MgSO₄), concentration, and chromatography (silica gel, 15% ethyl acetate/hexane; then 40% ethyl acetate/hexane) gave the crude title compound as a yellow oil. The residue was rechromatographed (silica gel, 25% ethyl acetate/hexane)to yield the title compound (1.36 g, 88%) as a light yellow oil. This material was used without separation of the isomeric reaction products.

f) methyl 3-methoxycarbonyl-4-[5-(t-butoxycarbonyl)-2-[[[N-(2-phenylethyl)-N-t-butoxycarbonyl]amino]methyl]-phenyl]butanoate

The compound of Preparation 1 (e) (1.18 g, 2.08 mmol) was dissolved in anhydrous methanol (21 mL), and palladium (II) hydroxide on carbon (0.21 g) was added. The resulting mixture was shaken at RT under H2 (47 psi) for 2 h, then was filtered through Celite®. The filtrate was concentrated and resubmitted to the same reaction conditions. After another 5.5 h, the mixture was filtered as before, and the filtrate was concentrated to afford the title compound (1.13 g, 95%) as a colorless oil.

g) methyl (R,S)-7-carboxy-2,3,4,5-tetrahydro-3-oxo-2-(2-phenylethyl)-1H-2-benzazepine-4-acetate

TFA (11 mL) was added all at once to a cloudy solution of the compound of Preparation 1 (f) (1.30 g, 2.28 mmol) in dry CH₂Cl₂ (11 mL) at 0°C under argon. The resulting light yellow solution was warmed to RT, stirred for 2 h, and concentrated. The residue was concentrated once from 1,2-dichloroethane to remove residual TFA and give methyl 3-methoxycarbonyl-4-[5-carboxy-2-[[N-(2-phenylethyl)amino]methyl]phenyl]butanoate as a pale green oil.

The oil was dissolved in anhydrous methanol (11 mL), and the solution was cooled to 0°C under argon. Freshly prepared 1.0 M sodium methoxide/methanol (11 mL, 11 mmol) was added and the ice bath was removed. The yellow solution was allowed to warm to RT over 5 min and heated to reflux under argon. After 3 h, the reaction was cooled in ice and quenched with glacial acetic acid (1.3 mL, 22.8 mmol). The reaction was diluted with ethyl acetate (100 mL) and washed with water. The combined aqueous layers were back-extracted with ethyl acetate, and the combined ethyl acetate layers were washed with brine, dried (MgSO₄), and concentrated to a pale green residue. Chromatography ((silica gel, 10% methanol/chloroform/0.1% acetic acid) gave the title compound as a yellow foam. Crystallization from methanol containing a little chloroform gave the title compound (528.2 mg, 61%) as an off-white solid. mp 214-216°C; TLC R_f 0.49 (10:90 methanol:chloro form).

h) methyl (R,S)-7-[[[4-[N-(benzyloxycarbonyl)-aminoiminomethyl]phenyl]methylamino] carbonyl]-2,3,4,5-tetrahydro-3-oxo-2-(2-phenylethyl)-1H-2-benzazepine-4-acetate

The compound of Preparation 1 (g) (117.9 mg, 0.31 mmol) was refluxed with thionyl chloride (3 mL) for 15 min and the yellow solution was concentrated. The residue was concentrated from dry toluene (3 mL) to remove residual thionyl chloride, and the resulting material was dissolved in dry CH₂Cl₂ (0.5 mL). This solution was added dropwise over 1-2 min to a solution of 4-(methylamino)-(N-benzyloxycarbonyl)benzamidine (263 mg, 0.93 mmol) and anhydrous pyridine (0.125 mL, 1.55 mmol) in dry CH₂Cl₂ (10 mL) at 0°C under argon. The resulting yellow mixture was warmed to RT and stirred for 0.5 h, diluted with ethyl acetate, and washed with 5% sodium bicarbonate. Drying (sodium sulfate), concentration, and chromatography (silica gel, 10% ethyl acetate/toluene) gave the title compound (174.8 mg, 87%) as a faintly yellow oil. TLC R_f 0.45 (9:1 toluene:ethyl acetate).

i) methyl (R,S)-7-[[[4-(aminoiminomethyl)phenyl]methylamino]carbonyl]-2,3,4,5-tetrahydro-3-oxo-2-(2-phenylethyl)-1H-2-benzazepine-4-acetate

10% Palladium on carbon (58 mg, 0.054 mmol) was added carefully to a solution of the compound of Preparation 1(h) (174.8 mg, 0.27 mmol) and TFA (0.021 mL, 0.27 mmol) in ethyl acetate/methanol (1:1,9 mL), and the mixture was stirred briskly under hydrogen (balloon pressure). After 1.5 h, the mixture was filtered through Celite®, and the filter pad was washed thoroughly with ethyl acetate and methanol. Concentration gave the title compound.

j) (R,S)-7-[[[4-(aminoiminomethyl)phenyl]methylamino]carbonyl]-2,3,4,5-tetrahydro-3-oxo-2-(2-phenylethyl)-1H-2-benzazepine-4-acetic acid

The compound of Preparation 1 (i) was dissolved in methanol (9 mL), and 1.0 N sodium hydroxide (0.81 mL, 0.81 mmol) was added. The solution was stirred at RT overnight, then was concentrated. The residue was dissolved in water/acetonitrile (3 mL), cooled to 0°C, and acidified with TFA (0.21 mL, 2.7 mmol). The faintly yellow solution was concentrated and the residue was purified by reversed-phase flash chromatography (C-18 silica gel, 25% AN/W-TFA). Concentration and lyophilization gave the title compound (123 mg, 67%) as a colorless powder. The following Examples illustrate the manner of making the pharmacologically active compounds and compositions of this invention.

Reference Example 1 Preparation of (R,S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-4-[2-(cyclohexyl)ethyl]-2,3,4,5-tetrahydro-3-oxo-1H-1,4-benzodiazepine-2-acetic acid a) methyl (R,S)-7-carboxy-4-[2-(cyclohexyl)ethyl]-2,3,4,5-tetrahydro-3-oxo-1H-1,4-benzodiazepine-2-acetate

A solution of methyl (R,S)-7-carboxy-2,3,4,5-tetrahydro-3-oxo-4-(2-phenylethyl)-1H-1,4-benzodiazepine-2-acetate (1.2 mmol) and 0.6N hydrochloric acid (4.0 mL) in methanol (50 mL) was treated with platinum oxide (120 mg) and hydrogenated (45 psi) and the mixture was filtered and concentrated to give the title compound.

b) methyl (R,S)-7-[(N-(t-butoxycarbonyl)-4,4'-bipiperidin-1-yl)carbonyl]-[2-(cyclohexyl)ethyl]-2,3,4,5-tetrahydro-3-oxo-4-1H-1,4-benzodiazepine-2-acetate

The compound of Reference Example 1 (a) (2.0 mmol) dissolved in DMF (30 mL) was treated with EDC (2.2 mmol) and 1-HOBT (285 mg, 2.1 mmol). This mixture was treated with N-(t-butoxycarbonyl)-4,4'-bipiperidine (2.4 mmol), stirred at RT for 48 h, concentrated and the residue was purified by flash chromatography to yield the title compound.

c) methyl (R,S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-4-[2-(cyclohexyl)ethyl]-2,3,4,5-tetrahydro-3-oxo-1H-1,4-benzodiazepine-2- acetate

The compound of Reference Example 1 (b) (0.56 mmol) was dissolved in a mixture of CH₂Cl₂ (25 mL) and TFA (5 mL). After 1 h, the mixture was concentrated to give the title compound.

d) (R,S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-4-[2-(cyclohexyl)ethyl]-2,3,4,5-tetrahydro-3-oxo-1H-1,4-benzodiazepine-2- acetic acid

The compound of Reference Example 1 (c) (0.3 mmol) was suspended in acetone (2 mL) and treated lithium hydroxide hydrate (25 mg) in water (2 mL). The mixture was stirred overnight, treated with methanol and additional lithium hydroxide hydrate (5.5 mg) was added in two portions over 9 h. The mixture was concentrated and the aqueous residue was neutralized with hydrochloric acid and concentrated. The residue was placed in the refrigerator overnight and filtered. The filter cake was washed with cold water, acetone and ether to yield the title compound Anal. [C₃₀H₄₄N₄O₄·2.5(C₂HF₃O₂) ·2(H₂O)] calcd: C,49.70; H,6.02; N,6.62. found: C,49.43; H,6.02; N,6.62.

Example 2 Preparation of (R,S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid a) t-butyl 3-methyl-4-nitrobenzoate

3-Methyl-4-nitrobenzoic acid (500 g, 2.76 mol) was added to pyridine (1.25 L) and stirred until it dissolved. Benzenesulfonyl chloride (609 g, 3.45 mol) was added rapidly while maintaining the internal temperature <30°C with an ice bath. A precipitate formed towards the end of the addition and pyridine (500 mL) was added to improve stirring. The mixture was stirred for 30 min and t-butanol (523 mL) was added dropwise over 30 min at < 30°C. The mixture was stirred for 2 h, dissolved in hexane:ethyl acetate (4:1; 2.5 L) and the resulting mixture was extracted with water. The organic phase was concentrated to give a light yellow oil which crystallized on cooling to give the title compound (635 g, 97%). mp 56-58°C.

b) t-butyl 3-bromomethyl-4-nitrobenzoate

A solution of the compound of Example 2 (a) (635 g, 2.68 mol) in carbon tetrachloride (6 L) was stirred and treated with N-bromosuccinimide (476.5 g, 2.68 mol). The mixture was irradiated and heated to reflux with 3 flood lamps positioned below the solution level. Benzoyl peroxide (6 g) was added in four portions while the mixture was heated to reflux and the last portion was added as reflux was reached after 2 h. The mixture was irradiated at reflux for 12 h, cooled, allowed to stand several hours, filtered and concentrated to a brown oil (870.7 g). The oil was taken up in hexane (3 L) and ether (500 mL) (boiling), filtered and the filtrate was partly concentrated by boiling. The resulting solution was allowed to stand overnight and the off-white crystalline solid which formed was filtered, washed with hexane and dried to give the title compound (396.6 g, 46.8%). mp 80-83°C; ¹H NMR (250 MHz) δ 4.5 (2H); TLC R_f O.7 (silica gel, 1:9 ethyl acetate/hexane). The filtrate yielded a second crop on standing (73 g). mp 61-65°C.

c) t-butyl 3-(methylamino)methyl-4-nitrobenzoate

Aqueous 40% methylamine (623 mL) was added to dimethylformamide (2.5 1) stirred at -5°C in an acetone/ice bath. A solution of the compound of Example 2 (b) (238 g, 0.753 mol) in ethyl acetate (600 mL) was added dropwise over 1 h while maintaining the internal temperature between 0°C and -5°C. The clear yellow reaction mixture was stirred for an additional 30 min and was diluted with an equal volume of water. Hexane was added, the organic phase was separated and the aqueous phase was extracted with hexane. The combined organic extracts were washed with water and concentrated to give the title compound (217.8 g) as a bright yellow oil.

d) t-butyl 3-[N-(t-butoxycarbonyl)-(methylamino)-methyl]-4-nitrobenzoate

A solution of the compound of Example 2 (c) (0.753 mol) in ethyl acetate (1 L) was stirred and treated with di-t-butyl dicarbonate (180.8 g, 0.828 mol) which was added in portions. A vigorous reaction occurred with rapid gas evolution which ceased after the final addition of the dicarbonate. The reaction mixture was stirred for an additional 30 min, and was extracted with 4% aqueous sodium carbonate and with water. The organic phase was concentrated to give a light yellow oil which was dissolved in hexane and cooled in a Dry Ice/acetone bath to initiate crystallization. The mixture was stored in the refrigerator, filtered and dried to give the title compound (129 g, 47%) which was used in the next step. mp 56-58°C. ¹H NMR (CDCl₃) δ 8.05 (2H, s), 7.95 (1H, s), 4.8 (2H, d), 2.9 (2H, s), 1.6 (9H, s), 1.5 (9H, s); HPLC t_R 27 min (Zorbax RX C₁₈, gradient, 4.6 X 150 mm, A:methanol B:water-0.1% TFA, 50-90% methanol during 40 min, UV detection at 210 nm).

e) t-butyl 4-amino-3-[N-(t-butoxycarbonyl)-(methylamino)methyl]benzoate

A solution of the compound of Example 2 (d) (129 g,0.352 mol) in ethyl acetate/methanol (1:1, 1.5 L) was treated with 10% Pd/C (40 g) moistened with ethyl acetate under argon in a hydrogenation bottle. The bottle was purged with hydrogen and shaken until the theoretical amount of hydrogen was absorbed. The mixture filtered through Celite® and the filtrate containing the title compound was used in the next step.

f) t-butyl (E/Z)-3-[N-(t-butoxycarbonyl)(methylamino)methyl]-4-[2-(1,4-dimethoxy-1,4-dioxo-2-butenyl)amino]benzoate

A solution of the compound of Example 2 (e)(118.3 g, 0.352 mol) in methanol:ethyl acetate (1.5 L) was stirred at RT under argon and dimethyl acetylenedicarboxylate (50 g, 0.352 mol) was added dropwise over 30 min and the mixture was heated to reflux for 16 h. The mixture was cooled and dimethyl acetylenedicarboxylate (6.0 mL, 0.0488 mol) was added in one portion. The reaction mixture was heated to reflux 2.5 h. The resulting solution containing the title compound was cooled and used in the next step.

g) t-butyl (R,S)-3-[N-(t-butoxycarbonyl)-(methylamino)-methyl]-4-[2-(1,4-dimethoxy-1,4-dioxobutyl)amino]benzoate

A solution of the compound of Example 2 (f) (∼168 g, 0.352 mol) in ethyl acetate:methanol (1.5 L) was added to 10% Pd/C (20 g) moistened with ethyl acetate under argon in a hydrogenation bottle. The mixture was shaken in a hydrogen atmosphere and heated to 48°C until the theoretical amount of hydrogen was absorbed, cooled, vented, filtered through Celite® and the filtrate was concentrated to give the title compound (173.4 g) as a yellow oil. HPLC t_R 18.9 min (Zorbax RX C₁₈, 4.6 X 150 mm, 1 mL/min, gradient, A:methanol B:water-0.1% TFA, 50-90% methanol over 40 min, UV detection at 210 nm).

h) (R,S)-4-[2-(1,4-dimethoxy-1,4-dioxobutyl)amino]-3-[(methylamino)methyl]benzoate

A solution of the compound of Example 2 (g) (0.348 mol) in dichloromethane (500 mL) was added over 30 min to a stirred solution of TFA (684 mL) and dichloromethane (1550 mL); the internal was between 18°C-25°C. The solution was stirred overnight at RT and concentrated to give the title compound (254.6 g) as a brown oil. HPLC t_R 19 min (Zorbax RX C₁₈ column, 4.6 X 150 mm, gradient, 1 mL/min, A:methanol B:water-0.1% TFA, 10-60% methanol over 50 min, UV detection at 210 nm).

i) methyl (R,S)-7-carboxy-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetate

A solution of the compound of Example 2 (h) [112.7 g (0.348 mol) with TFA (141.9 g)] in methanol (2 L) was cooled to between 0°C to -5°C and stirred under argon. Sodium methoxide in methanol (25%; 396 mL, 1.94 mol) was added over 2 h, maintaining the internal temperature between 0°C to -5°C. Following the addition, the temperature was allowed to rise slowly and the mixture stirred for 45 min. Glacial acetic acid (42 mL) was added to the reaction mixture followed by water (1.5 L). A crystalline precipitate began to form and the pH of the mixture was adjusted to 4.5 by careful additions of 12N hydrochloric acid. The mixture was stirred a few min, filtered and the precipitate washed with water and vacuum dried to give the title compound (77.6 g, 76%). ¹H NMR (250 MHz, DMSO_d6) δ 7.5 (2H, m), 6.5 (2H, m), 5.5 (1H, d), 5.2 (1H, m), 3.9 (1H, d), 3.6 (3H, s), 2.9 (3H, s), 2.9-2.6 (2H, m); mp 276-277°C, HPLC tR 23.2 min (Zorbax RX C18, 4.6 x 150 mm, 1 mL/min, gradient, A:methanol B:water-0.1% TFA, 10-60% methanol over 50 min, UV detection at 210 nm); Anal.(C₁₄H₁₆N₂O₅) calcd: C, 57.53; H, 5.52; N, 9.58. found: C, 57.27; H, 5.41; N, 9.17; mp 280-280.5°C (dec).

j) methyl (R,S)-7-[[1'-(t-butoxycarbonyl)-4,4'-bipiperidin-1-yl]carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetate

Using the procedure of Reference Example 1 (b), except substituting the compound of Example 2 (i) for methyl (R,S)-7-carboxy-2,3,4,5-tetrahydro-3-oxo-4-(2-cyclohexylethyl)-1H-1,4-benzodiazepine-2-acetate, gave the title compound.

k) methyl (R,S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetate

Using the procedure of Reference Example 1(c), except substituting the compound of Example 2 (j) for the compound of Reference Example 1 (b), gave the title compound.

l) (R,S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid

Using the procedure of Reference Example 1 (d), except substituting the compound of Example 2 (k) for the compound of Reference Example 1 (c) and substituting sodium hydroxide for lithium hydroxide, gave the title compound. Anal. [C₂₃H₃₂N₄O₄·2(C₂HF₃O₂)]·2.5(H₂O)] calcd: C, 46.22; H, 5.46; N, 7.99. found: C, 46.33; H, 5.45; N, 7.97.

Examples 3-4 Preparation of (R)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid; and (S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid a) The compound of Example 2 (j) was separated by chiral HPLC to give the following compounds:

• 3 (a). methyl (R)-7-[[1'-(t-butoxycarbonyl)-4,4'-bipiperidin-1-yl]carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetate. [α]D +140 (c 1,CH3OH); HPLC tR 12.9 min (Chiralcel OD, 21.2 x 250 mm, 10 mL/min, methanol, UV detection at 325 nm)
• 4(a). methyl (S)-7-[[1'-(t-butoxycarbonyl)-4,4'-bipiperidin-1-yl]carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetate. [α]D-142.5 (c 1,CH3OH); HPLC tR 15.1 min (Chiralcel OD, 21.2 x 250 mm, 10 mL/min, methanol, UV detection at 325 nm).

b) Using the procedure of Example 2 (k), except substituting the compounds of Example 3 (a) and 4 (a) for the compound of Example 2 (j) gave the following compounds:

• 3 (b). methyl (R)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetate. HPLC tR 14.3 min (Ultrasphere C18, 4.6 x 250 mm, 1.5 mL/min, gradient, A:acetonitrile B: water-0.1% TFA, 5-60% acetonitrile over 20 min, UV detection at 220 nm)
• 4 (b). methyl (S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetate. HPLC tR 14.61 min (Ultrasphere C18, 4.6 x 250 mm, 1.5 mL/min, gradient, A:acetonitrile B: water-0.1% TFA, 5-60% acetonitrile over 20 min, UV detection at 220 nm).

c) Using the procedure of Preparation 1 (j), except substituting the compounds of Example 3 (b) and 4 (b) for the compound of Preparation 1 (i) gave the following compounds:

• 3 (c). (R)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid : [α]D +92.4 (c 0.5,CH3OH); MS(ES) m/e 429 [M+H]+; 427 [M-H]-; HPLC tR 12.7 min (Ultrasphere C18, 4.6 x 250 mm, 1.5 mL/min, gradient, A:acetonitrile B: water-0.1% TFA, 5-60% acetonitrile over 20 min, UV detection at 220 nm); Anal.(C23H32N4O4·4.5 CF3CO2H·3.33 H2O) calcd: C, 37.44; H, 4.16; N, 5.29. found: C, 37.43; H, 3.81; N, 5.20.
• 4 (c). (S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid : [α]D -105.9 (c 0.6,CH3OH); MS(ES) m/e 429 [M+H]+; 427 [M-H]-; HPLC tR 12.6 min (Ultrasphere C18, 4.6 x 250 mm, 1.5 mL/min, gradient, A:acetonitrile B: water-0.1% TFA, 5-60% acetonitrile over 20 min, UV detection at 220 nm); Anal.(C23H32N4O4·3 CF3CO2H·1.25 H2O) calcd: C, 43.92; H, 4.77; N, 7.06. found: C, 44.09; H, 5.00; N, 7.29.

Example 5 Preparation of (S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid a) 4-fluoro-3-methylbenzoic acid

A solution of 4-fluoro-3-methylphenylmagnesium bromide in THF (1.0 M, 250 mL, 250 mmol) was added in a stream over 5 min to a mixture of Dry Ice (10 g) in dry THF (250 mL), and the reaction was allowed to warm to RT and concentrated. The residue was partitioned between water (500 mL) and ether (250 mL), and the layers were separated. The aqueous layer was washed with ether (2 x 250 mL) and acidified to pH 1 with concentrated hydrochloric acid. The resulting mixture was cooled in an ice bath and filtered. The solid was washed with water and dried to afford the title compound (25.92 g, 67%) as an off-white solid: ¹H NMR (400 MHz, CDCl₃) δ 7.90-8.02 (m, 2H), 7.09 (t, J=8.9 Hz, 1H), 2.34 (d, J =1.7 Hz, 3H); IR (chloroform) 3400-2300 (broad), 1694 cm^-1; MS(ES) m/e 155 [M+H]⁺; m/e 153 [M-H]-.

b) t-butyl 4-fluoro-3-methylbenzoate

Isobutylene was bubbled into a suspension of the compound of Example 5 (a) (3.08 g, 20 mmol) in anhydrous ether (15 mL) in a pressure bottle at -78°C to give a reaction volume of 50 mL. Trifluoromethanesulfonic acid (0.09 mL, 1 mmol) was added dropwise, and the vessel was tightly sealed and warmed to RT. After 4 h, the reaction was cooled and the vessel was opened. Aqueous 5% sodium bicarbonate was added, and the mixture was stirred in a warm water bath to remove the excess isobutylene. Ether was added and the layers were separated. The ether layer was washed with 5% sodium bicarbonate and with brine, and dried (MgSO₄). Concentration gave the title compound (3.83 g, 91%) as a yellow oil which was used without further purification: TLC (toluene) R_f0.73; ¹H NMR (250 MHz, CDCl₃) δ 7.77-7.89 (m, 2H), 7.01 (t, J=8.9 Hz, 1H), 2.30 (d, J=1.8 Hz, 3H), 1.59 (s, 9H); IR (CCl₄) 1715, 1369, 1296, 1258, 1167, 1124, 1117, 1105 cm^-1; MS(ES) m/e 443 [2M+Na]⁺, 421 [2M+H]⁺, 211 [M+H]⁺, 155 [M+H-C₄H₈]⁺.

c) t-butyl 4-fluoro-3-(methylaminomethyl)benzoate

A mixture of the compound of Example 5 (b) (3.83 g, 18.22 mmol), N-bromosuccinimide (3.57 g, 20.24 mmol), benzoyl peroxide (0.22 g, 0.91 mmol), and carbon tetrachloride (90 mL) was heated at reflux. After 16 h, the reaction was cooled in an ice bath, filtered, and the filtrate was concentrated. The residue was passed through a short pad of silica gel which was then washed with 20% ethyl acetate:hexane, and the filtrate was concentrated. The residue was dissolved in THF (90 mL), and 40% aqueous methylamine (7.9 mL, 91.1 mmol) was added rapidly. The reaction was stirred overnight and concentrated. The residue was diluted with ether and washed sequentially with 1.0 N sodium hydroxide, water, and brine. The organic phase was dried (MgSO₄), concentrated, and the residue was chromatographed (silica gel, 10% methanol in 1:1 ethyl acetate:chloroform) to give the title compound (2.58 g, 59%) as a yellow oil: TLC R_f 0.49 (silica gel, 10% methanol in 1:1 ethyl acetate/chloroform); ¹H NMR (250 MHz, CDCl₃) δ 7.97 (dd, J=7.3, 2.3 Hz, 1H), 7.90 (ddd, J=8.4, 5.2, 2.3 Hz, 1H), 7.07 (app t, 1H), 3.83 (s, 2H), 2.46 (s, 3H), 1.59 (s, 9H); IR (CCl₄) 1714, 1368, 1297, 1248, 1164, 1106 cm^-1; MS(ES) m/e 240 [M+H]⁺, 184 [M+H-C₄H₈]⁺.

d) t-butyl (S)-4-fluoro-3-[[[4-methoxy-1,4-dioxo-2-[[benzyloxycarbonyl]amino]butyl]methylamino]methyl]benzoate

Dicyclohexylcarbodiimide (453.9 mg, 2.2 mmol) was added to a solution of the compound of Example 5 (c) (478.6 mg, 2 mmol), N-Cbz-L-aspartic acid β-methyl ester [J. Am. Chem. Soc., 79, 5697 (1957); J. Am. Chem. Soc., 85, 2483 (1963)] (618.8 mg, 2.2 mmol), and 1-hydroxybenzotriazole hydrate (297.3 mg, 2.2 mmol) in anhydrous dimethylformamide (5 mL) at RT. After 24 h, the mixture was diluted with ether (25 mL) and filtered. The filtrate was concentrated, and the residue was diluted with ether (50 mL) and washed with water (2 x 10 mL) and brine (10 mL). Drying (MgSO₄), concentration, and chromatography (silica gel, 2:1 hexane:ethyl acetate) gave the title compound (0.87 g, 87%) as a colorless oil: TLC R_f0.44 (silica gel, 2:1 hexane:ethyl acetate); ¹H NMR (250 MHz, CDCl₃) mixture of amide rotamers; δ 7.75-8.00 (m, 2H), 7.15-7.45 (m, 5H), 7.00-7.15 (m, 1H), 5.72-5.92 (m, 1H), 4.91-5.25 (m, 3H), 4.45-4.63 (m, 2H), 3.66 (s, 3H), 3.13 and 2.89 (2 x s, 3H), 2.58-2.94 (m, 2H), 1.56 (s, 9H); IR (CCl₄) 3415, 3260, 1736, 1716, 1652, 1497, 1368, 1296, 1252, 1207, 1163, 1117, 1109 cm^-1; MS(ES) m/e 1027 [2M+Na]⁺, 1005 [2M + H]⁺, 503 [M+H]⁺, 447 [M+H-C₄H₈]⁺.

e) t-butyl (S)-4-fluoro-3-[[[4-methoxy-1,4-dioxo-2-aminobutyl]methylamino]methyl]benzoate

A mixture of the compound of Example 5 (d) (0.87 g, 1.73 mmol), 10% Pd/C (184 mg, 0.17 mmol), and methanol (17 mL) was shaken at RT under hydrogen (50 psi). After 1.5 h, the reaction was filtered through Celite® and concentrated. Chromatography (silica gel, 10% methanol in 1:1 ethyl acetate:chloroform) gave the title compound (579.8 mg, 91%) as a colorless oil: TLC R_f 0.50 (silica gel, 10% methanol in 1:1 ethyl acetate:chloroform); ¹H NMR (250 MHz, CDCl₃) mixture of amide rotamers; δ 7.80-8.05 (m, 2H), 7.02-7.18 (m, 1H), 4.55-4.88 (m, 2H), 4.15-4.28 (m, 1H), 3.71 and 3.70 (2 x s, 3H), 3.11 and 2.95 (2 x s, 3H), 2.76 (dd, J=16.3, 5.4 Hz, 1H), 2.48-2.67 (m, 1H), 1.74 and 1.57 (2 x s, 9H); IR (CCl₄) 3380, 1735, 1717, 1653, 1370, 1298, 1253, 1164, 1112 cm^-1; MS(ES) m/e 369 [M+H]⁺, 313 [M+H-C₄H₈]⁺.

f) methyl (S)-(-)-2,3,4,5-tetrahydro-7-(t-butoxycarbonyl)-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetate

A solution of the compound of Example 5(e) (416.1 mg, 1.13 mmol) and 2,6-di-t-butylpyridine (0.51 mL, 2.26 mmol) in anhydrous dimethyl sulfoxide (5.7 mL) was heated under argon in an oil bath at 120-125°C. After 17.5 h, the reaction was cooled in ice-water and diluted with water. The mixture was extracted with ethyl acetate, and the combined ethyl acetate layers were washed with water and brine. Drying (MgSO₄), concentration, and chromatography (silica gel, 3:2 ethyl acetate:hexane) gave the title compound (221.8 mg, 56%) as a nearly colorless solid: TLC R_f 0.41 (3:2 ethyl acetate/hexane); [α]_D -202.7° (c 1.0,CH₃OH); ¹H NMR (400 MHz, CDCl₃) δ 7.68 (dd, J=8.5, 1.8 Hz, 1H), 7.59 (d, J=1.8 Hz, 1H), 6.50 (d, J=8.5 Hz, 1H), 5.44 (d, J=16.4 Hz, 1H), 5.08-5.16 (m, 1H), 4.54 (br d, J=4.5 Hz, 1H), 3.76 (d, J=16.4 Hz, 1H), 3.75 (s, 3H), 3.08 (s,3H), 3.00 (dd, J=16.0, 6.9 Hz, 1H), 2.67 (dd, J=16.0, 6.3 Hz, 1H), 1.57 (s, 9H); IR (chloroform) 3560-3240 (br), 1731, 1695, 1663, 1610, 1369, 1302, 1252, 1171, 1146, 1134 cm^-1; MS(ES) m/e 719 [2M+Na]⁺, 697 [2M+H]⁺, 349 [M+H]⁺.

g) methyl (S)-(-)-7-carboxy-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetate

A solution of the compound of Example 5 (f) (176.4 mg, 0.506 mmol) in anhydrous dichloromethane (2.5 mL) was cooled to 0°C and deoxygenated through three evacuation/argon flush cycles. TFA (2.5 mL) was added dropwise over 3 min, and the resulting solution was stirred for 2 h, during which time the temperature rose to +15°C. The reaction was concentrated (20°C) and the residue was reconcentrated from toluene (35°C) to remove any residual TFA and give the title compound.

h) methyl (S)-(-)-7-[1-[1'-(t-butoxycarbonyl)-4,4'-bipiperidinyl]carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetate

The compound of Example 5 (g), 1-hydroxybenzotriazole hydrate (82 mg, 0.607 mmol), and 4-(t-butoxycarbonyl)-4,4'-bipiperidine (163 mg, 0.607 mmol) were dissolved in anhydrous dimethylformamide (2.5 mL), and the solution was cooled to 0°C under argon. Diisopropylethylamine (0.18 mL, 1.01 mmol) was added, followed by 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (116 mg, 0.607 mmol), and the reaction was warmed to RT. After 21 h, the reaction was concentrated and the residue was partitioned between water and chloroform. The layers were separated and the aqueous layer was extracted with chloroform. Drying (MgSO₄), concentration, and chromatography (silica gel, 10% methanol in 1:1 ethyl acetate:chloroform) gave the title compound (215.4 mg, 78%) as a yellow foam: TLC R_f 0.50 (10% methanol in 1:1 ethyl acetate:chloroform); [α]_D -140.2° (c 1.0,CH₃OH); ¹H NMR (400 MHz, CDCl₃) 8 7.08-7.15 (m, 2H), 6.52 (d, J=8.3 Hz, 1H), 5.44 (dd, J= 16.4 Hz, 1H), 5.06 (t, J=6.6 Hz, 1H), 3.90-4.80 (br m, 4H), 3.75 (s, 3H), 3.73 (d, J=16.4 Hz, 1H), 3.08 (s, 3H), 2.99 (dd, J=15.8, 6.6 Hz, 1H), 2.56-2.93 (m, 5H), 1.60-1.83 (m, 4H), 1.46 (s, 9H), 1.08-1.42 (m, 6H); IR(CCl₄) 3290, 1735, 1689, 1669, 1610, 1436, 1426, 1365, 1286, 1173 cm^-1; MS(ES) m/e 1085 (2M+H)⁺, 565 [M+Na]⁺, 543 [M+H]⁺, 502, 487 [M+H-C₄H₈]⁺.

i) (S)-(-)-7-[1-[4,4'-bipiperidinyl]-carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid

Using the procedure of Example 4 (b)-(c), the compound of Example 5 (h) was converted to the title compound.

Example 6 Preparation of (S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid a) 4-fluoro-3-cyanobenzoic acid

To a mixture of 2-fluoro-5-methylbenzonitrile (13.5 g, 0.1 mol), tetrabutylammonium bromide (1.61 g, 5 mmol), and ruthenium(III)chloride trihydrate (0.261 g, 1 mmol) in dichloromethane (150 mL) was added a solution of sodium hypochlorite (645 mL, 0.45 mol) which had been neutralized to pH 9 with 20% sulfuric acid. The reaction mixture was stirred and maintained at pH 9 by adding 20% sodium hydroxide solution at RT. After 3 h, the aqueous phase was separated and neutralized to pH 2 with 20% sulfuric acid and the solid which formed was filtered to give the title compound (3.4 g, 20%). mp 177-8°C. ¹H NMR (CDCl₃) δ 7.35 (t, J=8.70 Hz, 1H), 8.38 (m, 1H), 8.42 (m, 1H).

b) t-butyl 4-fluoro-3-cyanobenzoate

To a stirred solution of the compound of Example 6 (a)(100 mg, 0.6 mmol) in toluene (20 mL) at 80°C was added a solution of N,N-dimethylformamide di-t-butyl acetal (1 mL, 4 mmol) in toluene (2 mL) over 10 min. The reaction mixture was heated for 1 h, cooled, washed with saturated sodium bicarbonate, dried (MgSO₄), and concentrated to give the title compound (70 mg, 52%). MS(ES) m/e 222 [M+H]⁺. ¹H NMR (CDCl₃) δ 1.60 (9H, s), 7.29 (t, J=8.62 Hz, 1H) 8.25 (m, 1H), 8.28 (m, 1H).

c) N-[[2-cyano-4-t-butoxycarbonyl]phenyl]-L-aspartic acid β-methyl ester

A mixture of the compound of Example 6 (b) (6 g, 27 mmol), L-aspartic acid β-methyl ester hydrochloride (6.1 g, 33 mmol), and sodium bicarbonate (8.37 g, 100 mmol) in water (20 mL) and dimethyl sulfoxide (80 mL) was heated at 72°C for 24 h. The reaction mixture was diluted with ice cold dilute hydrochloric acid and extracted with ethyl acetate. The combined organic phase was extracted with cold saturated aqueous sodium bicarbonate. The basic extracts were combined, acidified to pH 2 with cold dilute hydrochloric acid, and extracted with ethyl acetate. The combined organic extract was dried (MgSO₄), and concentrated to give the title compound (7.1 g, 75%), MS(ES) m/e 349 [M+H]⁺; ¹H NMR (CDCl₃) δ 1.57 (s, 9H), 3.01 (m, 2H), 3.75 (s, 1H), 4.64 (m, 1H), 5.77 (d, J=8.49 Hz, 1H), 6.71 (d, J=8.93 Hz, 1H), 8.02 (dd, J=8.93, 1.85 Hz, 1H), 8.08 (d, J=1.89 Hz, 1H).

d) N-[[2-formyl-4-t-butoxycarbonyl]phenyl]-L-aspartic acid β-methyl ester

The compound of Example 6 (c) (7.0 g, 20 mmol) was dissolved in acetic acid (65 mL) and placed in a hydrogenation bottle. After cooling, wet Raney® nickel (14 g), water (65 mL) and pyridine (65 mL) were added. The resulting mixture was purged of oxygen with argon for 0.5 h, and shaken in a hydrogen atmosphere (50 psi) at 60°C for 5 h. The mixture was degassed, filtered and the filtrate was azeotroped with toluene at 50°C under high vacuum. The residual oil was taken up in ethyl acetate (300 mL) and washed with cold dilute hydrochloric acid, dried (MgSO₄), and concentrated to give the title compound as light orange amorphous solid (5.9 g, 84%). MS(ES) m/e 352 [M+H]⁺; ¹H NMR (CDCl₃) δ 1.59 (s, 9H), 3.00 (m, 2H), 3.74 (s, 1H), 4.77 (m, 1H), 6.73 (d, J=8.88 Hz, 1H), 8.03 (d, J=8.85 Hz, 1H), 8.20 (d, J=2.12 Hz, 1H), 9.20 (d, J=8.31 Hz, 1H), 9.88 (s, 1H).

e) N-[[2-(N-methyl)aminomethyl-4-t-butoxycarbonyl]phenyl]-L-aspartic acid β-methyl ester

A solution of the compound of Example 6 (d) (5.9 g, 16.7 mmol) in ethyl acetate (100 mL) in a hydrogenation bottle was purged of oxygen with argon for 0.5 h. Platinum oxide (0.6 g), anhydrous MgSO₄ (5.9 g, 49 mmol), and a solution of methylamine (3.2M in methanol, 150 mL, 480 mmol) were added. The resulting mixture was shaken in a hydrogen atmosphere (50 psi) for 5 h and let stand for 18 h at RT. After addition of acetic acid (75 mL) with cooling, the mixture was again shaken in a hydrogen atmosphere (50 psi) for 2 h, and filtered. The filtrate was concentrated and azeotroped with toluene and the residue was desalted through an XAD-2 (350 g) column eluted with water (1.5 L) followed by a 50% acetonitrile:water. Two fractions (300 mL) were collected, concentrated and the residue was freeze-dried to give an off-white powder. The powder was dissolved in dichloromethane (200 mL), concentrated and the residue was azeotroped with toluene, and dried to give the title compound (5.2 g, 85%). MS(ES) m/e 367 [M+H]⁺.

f) methyl (S)-7-(t-butoxycarbonyl)-2,3,4,5-tetrahydro-3-oxo-4-methyl-1H-1,4-benzodiazepine-2-acetate

To a solution of the compound of Example 6 (e) (5.2 g, 14.2 mmol) and triethylamine (2.0 mL, 14.4 mmol) in dichloromethane (250 mL) at RT under an argon atmosphere was added benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate (6.5 g, 14.7 mmol). The reaction mixture was stirred overnight at RT, and washed with an ice-cold solution of dilute hydrochloric acid, water, 5% sodium bicarbonate, saturated brine, and then dried (MgSO₄). The solution was filtered, concentrated and the residue was chromatographed (silica gel, 40% ethyl acetate:hexane) to give the title compound (1.1 g, 22%). MS(ES) m/e 349.2 [M+H]⁺; ¹H NMR (CDCl₃) δ 1.57 (s, 9H), 2.67 (dd, J=15.93, 6.30 Hz, 2H), 3.00 (dd, J=15.93, 6.77 Hz, 2H), 3.08 (s, 3H), 3.75 (s, 1H), 3.76 (d, J=16.44 Hz, 1H) 4.51 (d, J=4.61, 1H), 5.11 (m, 1H) 5.45 (d, J= 16.44 Hz, 1H), 6.50 (d, J=8.44 Hz, 1H), 7.55 (d, J=1.88 Hz, 1H), 8.20 (dd, J=8.48, 1.88 Hz, 1H); [α]_D -225.1° (c 1,CH₃OH).

g) methyl (S)-7-carboxy-2,3,4,5-tetrahydro-3-oxo-4-methyl- 1H-1,4-benzodiazepine-2-acetate

To a solution of the compound of Example 6 (f) (160 mg, 0.46 mmol) in dichloromethane (5 mL) was added 4M hydrogen chloride:dioxane (5 mL, 20 mmol) at RT under argon. The reaction mixture was stirred for 18 h. The suspension was concentrated to give the title compound as an off-white solid.

h) methyl (S)-7-[(4-t-butoxycarbonyl-4'-bipiperidin)-1-ylcarbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetate

The compound of Example 6 (g), 1-hydroxybenzotriazole (75 mg, 0.55 mmol), and 4-t-butoxycarbonyl-4'-bipiperidine were dissolved in anhydrous dimethylformamide (2.5 mL). Diisopropylethylamine (0.16 mL, 0.92 mmol) was added, followed by 1-(dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (105 mg, 0.55 mmol), and the reaction mixture was stirred overnight at RT under argon. The reaction mixture was partitioned between ice water (50 mL) and ethyl acetate (30 mL). The layers were separated and the aqueous phase was extracted with ethyl acetate (2x30 mL). The combined organic extract was dried (MgSO₄), concentrated and the residue was chromatographed (silica gel, 2% methanol:dichloromethane) to give the title compound (162 mg, 59%). MS(ES) m/e 599.0 [M+H]⁺; ¹H NMR (CDCl₃) δ 1.45 (s, 9H), 1.20 (m, 6H), 1.70 (m, 4H), 2.66 (dd, J=16.08, 6.04 Hz, 2H), 2.81 (br s, 4H), 2.98 (dd, J=16.08, 7.31 Hz, 2H), 3.06 (s, 3H), 3.71 (d, J=16.44 Hz, 1H), 3.73 (s, 1H), 3.76 (d, J=16.44 Hz, 1H) 4.13 (br s, 4H), 5.07 (m, 1H) 5.45 (d, J= 16.44 Hz, 1H), 6.52 (d, J=8.51 Hz, 1H), 7.09 (m, 2H); [α]_D -139.3° (c 1,CH₃OH).

i) (S)-7-[1-[4,4'-bipiperidinyl]carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid

Using the procedure of Example 4 (b-c), the compound of Example 6 (h) was converted to the title compound.

Example 7 Preparation of (S)-7-[[4,4'-bipiperidin-1-yl]carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid a) (S)-7-[[1'-(t-butoxycarbonyl)-4,4'-bipiperidin-1-yl]carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid

The compound of Example 4 (a) (2.85 g, 5.3 mmol) was taken up in 1:1 methanol:THF (30 mL), purged with argon, cooled and treated with 1N sodium hydroxide (6.3 mL, 6.3 mmol). The resulting solution was stirred at RT for 16 h under argon. The solution was concentrated, diluted with water (10 mL), and adjusted to pH 5 with 1M acetic acid (litmus paper). The solution was filtered and the solid was dried in vacuo to give title compound (2.46 g, 87%).

b) (S)-7-[[4,4'-bipiperidin]-1-ylcarbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid

The compound of Example 7 (a) (1.46 g, 2.77 mmol) was treated with 4M hydrogen chloride in dioxane (30 mL) for 1 h under argon. The solution was concentrated and the residue was taken up in water and adjusted to pH 9 (litmus paper) with concentrated ammonium hydroxide and the resulting solution was loaded onto an XAD-2 column (3 x 7.5 cm). The column was eluted with water followed by 50% acetonitrile:water. Fractions containing the product were combined and lyophilized to give the title compound (910 mg, 77%) which was recrystallized from aqueous acetone. mp (shrinking 193) 218-220°C; ¹H NMR (400 MHz, DMSO_d6) δ 1.0-3.9 (m, 26H), 6.5-8.5 (m, 5H); MS (ES) m/e 429.2 [M+H]⁺; HPLC k' 5.37 (VyDac C18, 4.5 x 250 mm, gradient, A:acetonitrile B:water-0.1% TFA, 5%-60% acetonitrile in 20 min, UV detection at 220 nm); [α]_D -180.3° (c 1, MeOH); Anal. (C₂₃H₃₂N₄O₄·2.33 H₂O) calcd: C, 58.71; H, 7.81; N, 11.91. found: C, 58.67; H, 7.79; N, 11.80.

Example 8 Preparation of (R,S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid

Using the procedure of Example 7 , except substituting the compound of Example 2 (j) for the compound of Example 4 (a), gave the title compound as a crystalline solid. mp (shrinking 193°C) 219-220°C; MS(ES) m/e 429 [M+H]⁺; HPLC k' 6.5 (Ultrasphere ODS, 4.5x250 mm, gradient, A:acetonitrile B:water-0.1% trifluoroacetic acid, 5-60% acetonitrile during 20 min, UV detection at 220 nm).

Example 9 Preparation of Sodium (R,S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetate

The compound of Example 8 (10 mg, 0.023 mmol) was taken up in water (1 mL) and 1M sodium hydroxide (0.024 mL, 0.024 mmol) was added. The resulting solution was lyophilized and the powder was crystallized from aqueous acetone to give the title compound as a crystalline solid (2 mg). mp 220-223°C [shrinking 204°C].

The foregoing is illustrative of the making and using of this invention. This invention, however, is not limited to the precise embodiments described herein, but encompasses all modifications within the scope of the claims which follow.

Claims (13)

1. A compound which is:

   (R,S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid

   or a pharmaceutically acceptable salt thereof.
2. A compound which is:

   (S)-7-[(4,4'-bipiperidin-1-yl)carbonyl]-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid

   or a pharmaceutically acceptable salt thereof.
3. A pharmaceutical composition comprising a compound according to any one of claims 1-2 and a pharmaceutically acceptable carrier.
4. The use of a compound according to any one of claims 1-2 in the manufacture of a medicament for inhibiting platelet aggregation.
5. The use of a compound according to any one of claims 1-2 in the manufacture of a medicament for treating myocardial infarction, thrombosis, embolism, dissecting anurysm, unstable angina, transient ischemia attack, stroke and infarct-related disorders, or restenosis following angioplasty, or for inhibiting reocclusion of an artery or vein following thrombolytic therapy.
6. The use of a compound according to any one of claims 1-2 and a thrombolytic agent in the manufacture of a medicament for inhibiting reocclusion of an artery or vein following thrombolytic therapy.
7. The use of a compound according to any one of claims 1-2 and an agent which inhibits platelet aggregation selected from a cyclooxegenase inhibitor, thromboxane antagonist, thromboxane synthesis inhibitor, heparin, thrombin inhibitor, ADP receptor inhibitor and ticlopidine in the manufacture of a medicament for inhibiting platelet aggregation.
8. The use of a compound according to any one of claims 1-2 in the manufacture of a medicament for inhibiting platelet aggregation in combination with an agent which inhibits platelet aggregation selected from a cyclooxegenase inhibitor, thromboxane antagonist, thromboxane synthesis inhibitor, heparin, thrombin inhibitor, ADP receptor inhibitor and ticlopidine.
9. The use according to claim 7 or 8 wherein the agent is aspirin.
10. The use according to claim 7 or 8 wherein the agent is warfarin.
11. The use according to claim 7 or 8 wherein the agent is clopidogrel.
12. A process for preparing a compound according to claims 1-2, which comprises treating a compound of formula (IV): wherein    A¹ is NH;    R is H or a carboxy protecting group;    R³ is methyl;    X is H; and    R^6' is 7-(4,4'-bipiperidin-1-yl)carbonyl, wherein the basic nitrogen is protected; with a reagent, in any order,

    (i) to remove the amino protecting group from R^6'; and, if necessary,

    (ii) to remove a carboxy protecting group from CO₂R; and

    (iii) form a pharmaceutically acceptable salt thereof.
13. A process for preparing a pharmaceutical composition comprising admixing a compound according to any one of claims 1-2 with a pharmaceutically acceptable carrier.