The peptidyl ester derivatives of 2,2-dichlorocyclopropanol and the am
ide derivative of 2,2-dichlorocyclopropylamine were prepred as novel m
echanism-based inactivators of alpha-chymotrypsin. The esters inactiva
ted alpha-chymotrypsin irreversibly but the amide did not show any irr
eversible inhibitory activity toward alpha-chymotrypsin.