Microscale Parallel Synthesis of Acylated Aminotriazoles Enabling the Development of Factor XIIa and Thrombin Inhibitors

Herein we report a microscale parallel synthetic approach allowing for rapid access to libraries of N‐acylated aminotriazoles and screening of their inhibitory activity against factor XIIa (FXIIa) and thrombin, which are targets for antithrombotic drugs. This approach, in combination with post‐screening structure optimization, yielded a potent 7 nM inhibitor of FXIIa and a 25 nM thrombin inhibitor; both compounds showed no inhibition of the other tested serine proteases. Selected N‐acylated aminotriazoles exhibited anticoagulant properties in vitro influencing the intrinsic blood coagulation pathway, but not extrinsic coagulation. Mechanistic studies of FXIIa inhibition suggested that synthesized N‐acylated aminotriazoles are covalent inhibitors of FXIIa. These synthesized compounds may serve as a promising starting point for the development of novel antithrombotic drugs. Anticoagulant advance: A microscale parallel synthetic approach toward N‐acylated aminotriazoles is reported, enabling the compounds’ screening against FXIIa and thrombin. This approach afforded low‐nanomolar FXIIa and thrombin inhibitors with no off‐targeting of the other tested serine proteases. Selected compounds were shown to be covalent inhibitors of FXIIa and demonstrated anticoagulant properties in vitro, influencing the intrinsic blood coagulation pathway.