Himbacine-derived thrombin receptor antagonists: c7-spirocyclic analogues of vorapaxar

Progress of thrombus formation and research on the structure-activity relationship for antithrombotic drugs

Many populations suffer from thrombotic disorders such as stroke, myocardial infarction, unstable angina and thromboembolic disease. Thrombus is one of the major threatening factors to human health and the prevalence of cardio-cerebrovascular diseases induced by thrombus is growing worldwide, even some persons got rare and severe blood clots after receiving the AstraZeneca COVID vaccine unexpectedly. In terms of mechanism of thrombosis, antithrombotic drugs have been divided into three categories including anticoagulants, platelet inhibitors and fibrinolytics. Nowadays, a large number of new compounds possessing antithrombotic activities are emerging in an effort to remove the inevitable drawbacks of previously approved drugs such as the high risk of bleeding, a slow onset of action and a narrow therapeutic window. In this review, we describe the causes and mechanisms of thrombus formation firstly, and then summarize these reported active compounds as potential antithrombotic candidates based on their respective mechanism, hoping to promote the development of more effective bioactive molecules for treating thrombotic disorders.

Biologically active metabolites in drug discovery

Biologically active metabolites are a valuable resource for development of drug candidates and lead structures for drug design. This digest highlights a selection of biologically active metabolites that have been used as new chemical entities for development or as lead structures for drug design.

Stereoselective Oxidative Cyclization of N-Allyl Benzamides to Oxaz(ol)ines

This study presents an enantioselective oxidative cyclization of N-allyl carboxamides via a chiral triazole-substituted iodoarene catalyst. The method allows the synthesis of highly enantioenriched oxazolines and oxazines, with yields of up to 94% and enantioselectivities of up to 98% ee. Quaternary stereocenters can be constructed and, besides N-allyl amides, the corresponding thioamides and imideamides are well tolerated as substrates, giving rise to a plethora of chiral 5-membered N-heterocycles. By applying a multitude of further functionalizations, we finally demonstrate the high value of the observed chiral heterocycles as strategic intermediates for the synthesis of other enantioenriched target structures.

Design and synthesis of potent PAR-1 antagonists based on vorapaxar

A series of novel vorapaxar analogues with different amino substitutes at the C-7, C-9a and aromatic substitutes at the C-4 position were designed, synthesized, and evaluated for their inhibitory activity to PAR-1. Several compounds showed good potency in antagonist activity based on the intracellular calcium mobilization assay and excellent pharmacokinetics profile in rats. Among these analogues, 3d exhibited excellent PAR-1 inhibitory activity (IC₅₀ = 0.18 μM) and the lower ability to cross the blood-brain barrier compared with vorapaxar (IC₅₀ = 0.25 μM). Compound 3d has the potential to be developed as a new generation of PAR-1 antagonists with a better therapeutic window.

Synthesis of novel and potent vorapaxar analogues

Unlocking novel and potent vorapaxar analogues by functionalisation of previously unexplored positions on the parent vorapaxar scaffold.