Syntheses of the potent angiotensin converting enzyme inhibitor (3S)-1-(carboxymethyl)-3-[[(1S)-1-carboxy-3-phenylpropyl]amino]- 2,3,4,5-tetrahydro-1H-[1]benzazepin-2-one (4b; CGS 14831) and the related monoester prodrug (17a; CGS 14824A) are described together with preparative details for six- and eight-membered ring analogues. Inhibitory potencies and in vivo biological activity of the compounds are discussed. The data indicate that 17a has a biological profile comparable to that of enalapril.