To provide the subject new compound active to suppress angiotensin converting enzyme and/or neutral endopeptidase and useful for the prevention or treatment of cardiovascular diseases, especially hypertension, congestive heart failure, glaucoma, renal diseases, etc.

The objective compound is expressed by formula I {A is a group of formula II [R1 and R12 are each independently H, an alkyl, an alkenyl, an aryl or the like; R2 is H, R11-S (R11 is H, an alkyl, a substituted alkyl or the like) or the like; R3 is H, an alkyl or the like; (r) is 0 or 1] or the like; R13 and R14 are each independently H, an alkyl, an aryl, a halogen or the like; (n) is 0 or 1} or its pharmacologically permissible salt such as [3R-[3α,6α(S*),11 bβ]]-2,3,5,6,7,11b-hexahydro-6-[(2-mercapto-1-oxo-3-phenylpropyl)amino]-5-oxo- thiazolo[2,3-a][2]benzazepine-3-carboxylic acid. The compound of formula I can be produced by using a specific glycine derivative as a starting substance.