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β-Lactamase inhibitors with a bicyclic urea core and a variety of heterocyclic side chains were prepared and evaluated as potential partners for combination with imipenem to overcome class A and C β-lactamase mediated antibiotic resistance. The piperidine analog 3 (MK-7655) inhibited both class A and C β-lactamases in vitro. It effectively restored imipenem's activity against imipenem-resistant Pseudomonas and Klebsiella strains at clinically achievable concentrations. A combination of MK-7655 and Primaxin® is currently in phase II clinical trials for the treatment of Gram-negative bacterial infections.

A series of 19-substituted androstenediol derivatives was prepared. Some of the novel analogs were surprisingly potent and selective ligands for ER-beta.

Through directed screening of metalloprotease inhibitors, CGS 30084 (1) has been identified as a potent endothelin-converting enzyme-1 (ECE-1) inhibitor in vitro (IC50=77 nM). Herein we report the syntheses and biological activities of analogues derived from this lead, based on modifications of the biphenyl moiety. Compound 10, the thioacetate methyl ester prodrug derivative of compound 6m, was found to be an orally active and potent inhibitor of ECE-1 activity in rats.

The enantiomerically enriched BOC-protected (4-pinacolylborono)phenylalanine methyl ester (8) is produced via enzymatic resolution of the racemic material, or direct synthesis from the corresponding iodide (or triflate), and undergoes Suzuki-Miyaura coupling reactions with aromatic halides and triflates in the presence of catalytic amounts of PdCl2(dppf) to produce enantiomerically enriched 4-substituted phenylalanine derivatives.

The Boc-derivative of (4-pinacolylborono)phenylalanine ethyl ester (6) or the corresponding boronic acid 8 undergo Suzuki-Miyaura coupling reactions with aromatic chlorides in the presence of catalytic amounts of PdCl2(PCy3)2 or NiCl2(dppf), respectively, to produce 4-substituted phenylalanine derivatives.

The benzophenone imine of (4-pinacolylborono)phenylalanine ethyl ester ( 3 ) undergoes Suzuki-Miyaura coupling reactions with organic halides and triflates to give 4 -substituted phenylalanine derivatives. A homochiral boronate ester ( 7 ), derived from Seebach's chiral imidazolidinone template, yields the corresponding coupling products under similar conditions with no or little loss of stereochemical integrity.

Enantiomerically pure pyrrolidinones were synthesized as endothelin receptor antagonists. A [2+2] cycloaddition of an imine and an enantiomerically pure acid chloride gave two diastereomeric β-lactams which were separated and rearranged to give the enantiomerically pure pyrrolidinones which could be reduced to give the corresponding pyrrolidines.

α-Mercaptoacyl dipeptides were prepared and found to inhibit angiotensin converting enzyme (ACE) and neutral endopeptidase 24.11 (NEP). Compounds with a proline as the C-terminal amino acid, and possessing the S-stereochemistry at the thiol bearing carbon were preferred for optimal ACE inhibition while, R-stereochemistry was preferred for optimal NEP inhibition. Compounds containing alternative amino acid residues at the C-terminal position displayed optimal dual ACE/NEP inhibition when the stereochemistry was ‘S’ at this carbon atom.

Analogs of captopril and enalapril with a thiorphan-like substituent at the 4-position of the proline ring were synthesized and found to be dual inhibitors of angiotensin converting enzyme (ACE) and neutral endopeptidase 24.11 (NEP).

Indole rings substituted with two electron withdrawing groups were alkylated on the nitrogen under Mitsunobu reaction conditions.

A new class of potent, selective, nonsteroidal inhibitors of aromatase have been discovered. The most potent member of this series is fadrozole hydrochloride, CGS 16949 A, 4-(5,6,7,8-tetrahydroimidazo[1,5-alpha]pyridin-5-yl)benzonitrile monohydrochloride, 26a. In addition, the 6,7-dihydropyrrolo[1,2-c]imidazole (21a) and the 6,7,8,9-tetrahydroimidazo[1,5-alpha]azepine (21b) analogues were synthesized and evaluated. CGS 16949 A's ability to selectively inhibit aromatase (IC50 = 4.5 nM) over other cytochrome P-450 enzymes and suppress estrogen production when administered orally make it a suitable candidate to test the potential of an aromatase inhibitor in estrogen-dependent diseases including breast cancer.

Enantiomerically pure pyrrolidinones were synthesized as endothelin receptor antagonists. A [2+2] cycloaddition of an imine and an enantiomerically pure acid chloride gave two diastereomeric β-lactams which were separated and rearranged to give the enantiomerically pure pyrrolidinones which could be reduced to give the corresponding pyrrolidines.

The benzophenone imine of (4-pinacolylborono)phenylalanine ethyl ester ( 3 ) undergoes Suzuki-Miyaura coupling reactions with organic halides and triflates to give 4 -substituted phenylalanine derivatives. A homochiral boronate ester ( 7 ), derived from Seebach's chiral imidazolidinone template, yields the corresponding coupling products under similar conditions with no or little loss of stereochemical integrity.

The Boc-derivative of (4-pinacolylborono)phenylalanine ethyl ester (6) or the corresponding boronic acid 8 undergo Suzuki-Miyaura coupling reactions with aromatic chlorides in the presence of catalytic amounts of PdCl2(PCy3)2 or NiCl2(dppf), respectively, to produce 4-substituted phenylalanine derivatives.

The enantiomerically enriched BOC-protected (4-pinacolylborono)phenylalanine methyl ester (8) is produced via enzymatic resolution of the racemic material, or direct synthesis from the corresponding iodide (or triflate), and undergoes Suzuki-Miyaura coupling reactions with aromatic halides and triflates in the presence of catalytic amounts of PdCl2(dppf) to produce enantiomerically enriched 4-substituted phenylalanine derivatives.

(3-Pyridinyl)alkanoic acids substituted at the 4-position with an (arylsulfonamido)alkyl group were synthesized and found to behave as platelet thromboxane receptor antagonists (TxRAs) and thromboxane synthase inhibitors (TxSIs). The compounds behaved as agonists at the vascular receptor for thromboxane A2.

Arylsulfonylamino arylalkanoic acids substituted with a pyridinylalkyl group on the arylalkanoic acid portion of the molecule were synthesized and found to behave as thromboxane receptor antagonists (TxRAs) and thromboxane synthase inhibitors (TxSIs). One of these compounds (11), with a 1,3,5-trisubstituted central aromatic ring was demonstrated to have good functional bioavailability and efficacy as a platelet inhibitor in guinea pigs.

A series of 8-[(arylsulfonyl)amino]octanoic acids substituted with a pyridinylalkyl group along the chain were synthesized and tested in vitro for their ability to both antagonize the binding of thromboxane A2 to its receptors and to inhibit the thromboxane synthase enzyme. This series of compounds were found to inhibit the U 46619-induced aggregation of human platelets and the U 46619-induced contraction of dog saphenous vein. The compounds also inhibited TxA2 biosynthesis in a human microsomal platelet preparation. The relative position of the pyridinylalkyl and arylsulfonamide groups had significant effects on the thromboxane receptor antagonist (TxRA) activity and thromboxane synthase inhibitor (TxSI) activity. Compounds with the pyridine ring at the 7- or 8-position of the octanoic acid side chain were weakly active as TxSI but behaved as potent TxRA at the platelet receptor for TxA2. However, these compounds were agonists at the vascular receptor. Substitution of the pyridinylalkyl group at the 2- or 3-position resulted in compounds with potent TxSI activity and weak TxRA activity. The activity profile of the compounds with the pyridinylalkyl substitution at the 4-, 5-, or 6-position was very desirable. Compound 22 with a pyridinylpropyl substituent at the 4-position was found to display extremely potent TxRA and TxSI properties.

The title compound (10a) and its analogs were synthesized and found to possess two activities, the inhibition of the biosynthesis of thromboxane A2 and antagonism of its receptors. The in vitro and in vivo profile of these compounds as thromboxane receptor antagonists (TxRAs) and thromboxane synthase inhibitors (TxSIs) is described. 10a and its analogs displayed very potent TxRA activity in human washed platelets (IC50 approximately 10(-7)-10(-9) M) and dog saphenous vein (pA2 approximately 9) and also potent TxSI activity (IC50 approximately 10(-9) M). The good bioavailability and the long duration of action of some of these compounds was demonstrated using ex vivo measurement of the TxRA activity upon oral administration to guinea pigs. Compounds 10a, 20, and 33 potently inhibited arachidonic acid induced bronchoconstriction in guinea pigs.

A new class of potent, selective, nonsteroidal inhibitors of aromatase have been discovered. The most potent member of this series is fadrozole hydrochloride, CGS 16949 A, 4-(5,6,7,8-tetrahydroimidazo[1,5-alpha]pyridin-5-yl)benzonitrile monohydrochloride, 26a. In addition, the 6,7-dihydropyrrolo[1,2-c]imidazole (21a) and the 6,7,8,9-tetrahydroimidazo[1,5-alpha]azepine (21b) analogues were synthesized and evaluated. CGS 16949 A's ability to selectively inhibit aromatase (IC50 = 4.5 nM) over other cytochrome P-450 enzymes and suppress estrogen production when administered orally make it a suitable candidate to test the potential of an aromatase inhibitor in estrogen-dependent diseases including breast cancer.

A series of androstene-3,5-diene derivatives were prepared. Despite lacking the C-3 hydroxyl previously believed necessary for ER activity, some of the analogs retained surprising affinity for ER-beta. For example, diene 4 retained excellent selectivity and potency as an ER-beta agonist and was more selective for ER-beta over the androgen receptor (AR).

A series of benzoxathiin SERAMs with bicyclic amine side chains was prepared. Minor modifications in the side chain resulted in significant effects on biological activity, especially in uterine tissue.

Directed screening of metalloprotease inhibitors identified CGS 30084 ( 1 ) as a potent inhibitor of endothelin-converting enzyme-1 (ECE-1) in vitro (IC 50 =77 nM). Herein we report the syntheses and biological activities of analogues containing modified biphenyl moieties, bearing heterocyclic proximal rings. Compound 20 , the thioacetate ethyl ester prodrug derivative of compound 19a , was found to be an orally active and potent inhibitor of ECE-1 activity in rats.

The enantiomers of 8-[[(4-chlorophenyl)sulfonyl]amino]-4-(3-pyridinylpropyl)octanoic acid (1) and its pyridinyl ether analog (2) were synthesized using the highly diastereoselective method of alkylation of acyloxazolidinone. These enantiomerically pure compounds were compared with the corresponding racemic compounds 1 and 2 for their in vitro activity. Compounds 1, 1R, and 1S and 2,2S, and 2R were equipotent as thromboxane receptor antagonists (TxRAs) and thromboxane synthase inhibitors (TxSIs) (IC50 = 2-30 nM). Upon oral administration to guinea pigs, the enantiomers inhibited the ex vivo U 46619-induced platelet aggregation with potency similar to that of the corresponding racemic compound. This indicates that the enantiomers have pharmacologic profile and bioavailability similar to that of the corresponding racemic compound.

The design, synthesis, and in vitro pharmacology of a new class of compounds exerting both thromboxane receptor antagonist and thromboxane synthase inhibitory activities is described. [(3-Pyridinyl)bicycloheptyl] alkanoic acid 9 and its analogues, designed with the help of molecular modeling, were synthesized and found to be inhibitors of thromboxane A2 (TxA2) biosynthesis in a human platelet microsomal preparation. The compounds were also found to antagonize both platelet and vascular TxA2 receptors. The compounds inhibited the U 46619 induced aggregation of human washed platelets and platelet-rich plasma and the U 46619 induced contraction of the dog saphenous vein.

The preparation of a series of 1-glutarylindoline-2(S)-carboxylic acid derivatives, 6a-v and 21a-c, is described. The above compounds were tested for inhibition of angiotensin converting enzyme. The structure-activity relationship of the series is also discussed. Compound 6u, the most potent member of the series, had an in vitro IC50 of 4.8 X 10(-9) M. Compound 6v, an ethyl ester of 6u, lowered blood pressure 70 mm in spontaneous hypertensive rats at an oral dose of 30 mg/kg.

The synthesis and structure-activity profile of a new class of potent and highly specific thromboxane A2 synthetase inhibitors is described. The most potent member of this series in vitro is determined to be imidazo[1,5-a]-pyridine-5-hexanoic acid (9).

The synthesis and structure-activity profile of a new class of potent and highly specific thromboxane A2 synthetase inhibitors is described. The most potent member of this series in vitro is determined to be imidazo[1,5-a]-pyridine-5-hexanoic acid (9).

Numerous β-lactamase inhibitors have been developed to overcome the problems of bacterial resistance to β-lactam antibiotics. One such agent, clavulanic acid, has been combined with amoxicillin, and the combination is effective against many amoxicillin-resistant organisms. Clinical studies have demonstrated the efficacy of amoxicillin/clavulanate in a variety of infections, however, comparative studies are few and have not demonstrated sufficiently the superiority of the combination over conventional antibiotic therapy. In addition, side effects appear to be more frequent than with amoxicillin alone. The place in therapy of amoxicillin/clavulanate is discussed.