PURPOSE: To obtain an antihypertensive agent which is an angiotensin converting enzyme inhibiotor by reacting a compound such as a 3-thiopropionic acid derivative with an amino acid derivative.
CONSTITUTION: A compound of formula I (R1 is H, methyl; R2 is L-proline, L-3,4-dehydroproline, L-3-hydroxyproline, L-thiazolysine-4-carboxylic acid, etc., its imino is imino-bonded to adjacent CO; n is 0, 1; when n is O, R is methyl, when n is 1 and R1 is methyl, formula II part is D-structure) is reacted with a compound of a formula R-A (R is H, t-butyloxycarbonyl, cyclopentane carbonyl-L-lysyl, L-lysyl, L-arginyl, etc.; A is phenylalanyl, tryptophyl, tyrosyl, glycyl, leucyl, etc., its α-amino group is amide-bonded to R) to obtain a compound of formula III, for example, Nα-[3-(Nα-benzoyl-phenylalanylthio)-2-D- methylpropanol]-L-proline.
CHUNG ALFRED