2-(2-Chloro-6-fluorophenyl) acetamides having 2, 2-difluoro-2-aryl/heteroaryl-ethylamine P3 and oxyguanidine P1 substituents are potent thrombin inhibitors (Ki= 0.9–33.9 nM). 2-(5- Chloro-pyridin-2-yl)-2, 2-difluoroethylamine was the best P3 substituent, yielding the most potent inhibitor (Ki= 0.7 nM). Replacing the P3 heteroaryl group with a phenyl ring or replacing the difluoro substitution with dimethyl or cyclopropyl groups in the linker reduced ...
