Design, synthesis and in vitro activities of a series of benzimidazole/benzoxazole glycoprotein IIb/IIIa inhibitors

Synthesis and Biological Evaluation of (E)-N’-Benzylidene-7-methyl-2-propyl-1H-benzo[d] imidazole-5-carbohydrazides as Antioxidant, Anti-inflammatory and Analgesic agents

(E)-N’-Benzylidene-7-methyl-2-propyl-1H-benzo [d]imidazole-5-carbohydrazides (5a-r) have been synthesized from 7-methyl-2-propyl-1H-benzo[d]imidazole-5-carbohydrazide (3) by condensing with different aromatic aldehydes (4a-r). Title compounds (5a-r) were evaluated for in vitro antioxidant activity and based on their potential for antioxidant property, selected compounds 5d and 5m-p were screened for in vivo anti-inflammatory and analgesic activity. The results indicate that the compound 5o and 5p are effective against anti-inflammatory and analgesic activity. The biological data was further supported by molecular docking studies, which revealed the binding pattern and the affinity of the molecules in the active site of COX-2.

Progress in the research of GPIIb/IIIa antagonists

This review covers the recent advances in the development of small RGD (Arg-Gly-Asp sequence) containing peptides and their mimetics as potential antithrombotic agents. Glycoprotein IIb/IIIa (GPIIb/IIIa) antagonists include monoclonal antibodies, RGD peptides, peptide hybrids and nonpeptide mimetics. The current trend in the development of nonpeptide mimetics is clearly directed toward orally active and safe antithrombotic drug candidates. But several nonpeptide mimetics, being evaluated for their oral activity in human clinical trials, are currently not approved for clinical use due to poor safety profile. It is expected that newer and more effective nonpeptide mimetics will be developed in the near future.

RGD mimetics containing phthalimidine fragment as novel ligands of fibrinogen receptor

The novel RGD mimetics with phthalimidine central fragment were synthesized with the use of 4-piperidine-4-yl-butyric, 4-piperidine-4-yl-benzoic, 4-piperazine-4-yl-benzoic and 1,2,3,4-tetrahydroisoquinoline-7-carboxylic acids as surrogates of Arg motif. The synthesized compounds potently inhibited platelet aggregation in vitro and blocked FITC-Fg binding to α(IIb)β(3) integrin in a suspension of washed human platelets. The key α(IIb)β(3) protein-ligand interactions were determined in docking experiments.

Non-peptide alpha(v)beta(3) antagonists. Part 5: identification of potent RGD mimetics incorporating 2-aryl beta-amino acids as aspartic acid replacements

A series of novel, highly potent alpha(v)beta(3) receptor antagonists with favorable pharmacokinetic profiles has been identified. In this series of antagonists, 2-aryl beta-amino acids function as potent aspartic acid replacements.

Design and synthesis of a series of indole glycoprotein IIb/IIIa inhibitors

Synthesis of 1,3-disubstituted indoles derivatives as potential glycoprotein (GP) IIb/IIIa antagonists was reported. Substitution of the indolic nitrogen atom by piperidino or benzamidino moieties was used as mimics of an arginine residue. The acid carboxylic group was linked to the indole scaffold in position-3 via a methylene unit (compounds 4, 9, 10). Introduction of a beta-alanine chain was carried out on the acids (17-22) which after deprotection and basic hydrolysis afforded the final compounds 39-46. The distance between the indole scaffold and the amide bond was modulated from no methylene unit (compound 39) to 1 (compounds 40, 41) or 2 methylene units (compounds 42-46). The presence of a tosylamino group on the beta-alanine chain (compound 56) slightly increased the inhibiting action on platelet aggregation initiated by collagen.

Mass spectrometric and NMR characterization of metabolites of roxifiban, a potent and selective antagonist of the platelet glycoprotein IIb/IIIa receptor

1. The methyl ester prodrug roxifiban is an orally active, potent and selective antagonist of the platelet glycoprotein GPIIb/IIIa receptor and is being developed for the prevention and treatment of arterial thrombosis. 2. Roxifiban was rapidly hydrolyzed to the zwitterion XV459 in vivo and by liver slices from the rat, mouse and human and by intestinal cores from dog. XV459 was metabolized to only a small extent in vitro and in vivo. 3. Studies with rat and dog given radiolabelled roxifiban showed limited oral absorption with the majority of the radiolabel being excreted in faeces. After i.v. doses of 14C-roxifiban, most of the radioactivity was recovered in the urine of rat whereas the dog excreted significant amounts of radioactivity in bile and urine. 4. XV459 could be metabolized extrahepatically by dog gut flora to produce an isoxazoline ring-opened metabolite. In vitro hepatic metabolism of XV459 was mainly by hydroxylation at the prochiral and chiral centres of the isoxazoline ring. These hydroxylated metabolites were not detected in the urine and plasma of human volunteers administered roxifiban. 5. Initial LC/MS identification of metabolites was achieved by dosing the rat with an equimolar mixture of d0:d4 roxifiban and detecting isotopic clusters of pseudomolecular ions. Unequivocal characterization of these metabolites was achieved by LC/MS, LC/NMR and high-field NMR techniques using synthetic standards of the metabolites. 6. The synthesis of one hydroxylated metabolite enabled the assignment of the correct stereochemistry of the substituted hydroxyl group on the isoxazoline ring.

Platelet glycoprotein IIb/IIIa receptor antagonists derived from isoxazolidines

A series of isoxazolidines has been synthesized as mimetics of the RGD sequence and was evaluated as antagonists of the platelet glycoprotein IIb/IIIa receptor. These compounds were shown to be highly potent GPIIb/IIIa antagonists, exhibiting submicromolar potencies.

Synthesis and antiplatelet effects of an isoxazole series of glycoprotein IIb/IIIa antagonists

Despite the excellent in vitro potency of a series of benzamide glycoprotein IIb/IIIa antagonists, which have been reported previously, poor in vivo potency in the inhibition of platelet aggregation was observed when the most potent inhibitor XU057 was dosed intravenously to dogs. In this communication, we report that replacement of the benzamide in XU057 with an isoxazolecarboxamide resulted in significant improvement in in vivo potency. More importantly, the analogue XU065 showed an excellent oral antiplatelet effect in dogs.

Minimized proteins

The design of bioactive small molecules for interaction at larger protein-protein interfaces remains a challenge. Recent progress towards minimizing proteins into significantly smaller polypeptides has been achieved via both rational design processes and selection from vast combinatorial libraries. Such 'mini-proteins' represent a potential intermediate step toward the development of drugs targeted to protein-protein interfaces.

Design, synthesis, and in vitro activities of benzamide-core glycoprotein IIb/IIIa antagonists: 2,3-diaminopropionic acid derivatives as surrogates of aspartic acid

In an effort to discover novel nonpeptide glycoprotein IIb/IIIa (GPIIb/IIIa, alpha IIb/beta 3) inhibitors, we investigated RGD mimetics featuring a 3-substituted benzoic acid as the core, benzamidine as the basic moiety, and a series of beta- and alpha-substituted beta-alanine derivatives as aspartic acid surrogates. It was found that the use of beta-methyl beta-alanine slightly improved the anti-aggregant potency in human platelet-rich plasma over the unsubstituted beta-alanine compound, while beta-substitution with a trifluoromethyl group resulted in considerable loss in activity. Significant enhancement (up to 100-fold) in potency was obtained when the beta-alanine was replaced with N2-substituted 1-2,3-diaminopropionic acid derivatives. Among the three types of alpha-substituents (carbamate, amide, and sulfonamide) investigated, no apparent preference was observed with respect to in vitro potency. However, alkyl groups were more favorable than arylalkyl groups (Cbz) in the carbamate analogues. We also investigated piperidine, piperazine, and N-formamidinopiperidine as replacements for the benzamidine moiety. The former two replacements led to a drop in potency while the latter replacement resulted in maintenance of activity as compared with the corresponding benzamidine analogue.