Since activated factor X (FXa) is a coagulant enzyme that generates thrombin and participates in both intrinsic and extrinsic coagulation pathways, inhibition of FXa may be more effective than inactivation of thrombin for interrupting blood coagulation. To assess the possible effectiveness of FXa inhibition as an anticoagulant, we designed and synthesized 3-(amidinoaryl)-2-[4-[(3S)-3-pyrrolidinyloxy]phenyl]propanoi c acid derivatives as low molecular weight, nonpeptidic, orally active FXa inhibitors. These derivatives exhibited potent and highly selective anti-FXa activity in vitro and anticoagulant activity on oral administration. The most promising compound, (2S)-2-[4-[[(3S)-1-acetimidoyl-3-pyrrolidinyl]oxy]phenyl]- 3-(7-amidino-2-naphthyl)propanoic acid hydrochloride pentahydrate (4,DX-9065a), inhibited 50% of FXa activity (IC50) at 0.07 microM, doubled plasma recalcification time (PRCT) at 0.5 microM, and significantly prolonged activated partial thromboplastin time (APTT) at a dose of 100 mg/kg on oral administration. In contrast with FXa inhibition, 4 showed no activity against thrombin (IC50 > 2000 microM).

A series of novel 1,2,3,5-tetrahydroimidazo[2,1-b]quinazolin-2-one derivatives substituted with a secondary amino group has been prepared and tested for the activities of inhibiting platelet aggregation in rats in vitro and ex vivo. Most of the compounds were found to be the potent inhibitors of platelet aggregation. Some of the active compounds were soluble in water and effective via iv infusion in rats. Structure-activity relationships have indicated that a lipophilic secondary amino group located at position 6 or 7 contributed to retention of potent activity. Among the compounds studied, 7-piperidino-1,2,3,5-tetrahydroimidazo[2,1-b]quinazolin-2- one (13 g,DN-9693) was the most favorable compound.

No abstract

No abstract

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.