Bicyclic lactam inhibitors of angiotensin converting enzyme

Syntheses of the potent angiotensin converting enzyme inhibitor 1-(carboxymethyl)-3-(mercaptomethyl)-2,3,4,5-tetrahydro-1H-1- benzazep in -2-one (4a) and the corresponding eight-membered ring analogue (4b) are described. The influence of ring size on the inhibitory potencies of these substances is discussed.