Abstract: This paper reports the synthesis of nine N-(4-carbethoxy-4-substituted butyryl)-N-substituted glycines and their corresponding t-butyl esters. The former were expected to have inhibitory activity of angiotensin-converting enzyme. All of the compounds mentioned above were unreported in the literature. In preliminary test in rats, compounds Ⅶ₇ and Ⅶ₉ showed marked hypotensive activity.