Quinapril is a (3S)-2-L-alanyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid derivative in which the alpha-amino group of the alanyl residue is substituted by a 1-ethoxycarbonyl-4-phenylbutan-2-yl group (the all-S isomer). It is a prodrug of quinaprilat, converted by hydrolysis of the ethyl ester to the corresponding carboxylic acid. Quinapril is an angiotensin-converting enzyme (ACE) inhibitor, typically used as the hydrochloride salt, for the treatment of hypertension and congestive heart failure. It functions as an EC 3.4.15.1 (peptidyl-dipeptidase A) inhibitor, a prodrug, and an antihypertensive agent. It belongs to the classes of isoquinolines, dicarboxylic acid monoesters, ethyl esters, and tertiary carboxamides.
