Mercapto-acylamino acids as antihypertensives

A compound having the structural formula ##STR63## wherein R.sub.1 is H or R.sub.5 CO--;

• R.sub.2 is Y--C.sub.6 H.sub.4 --, Y--C.sub.6 H.sub.4 S--, Y--C.sub.6 H.sub.4 O--, Y--C.sub.6 H.sub.4 CH.sub.2 S--, Y--C.sub.6 H.sub.4 CH.sub.2 O--, .alpha.-naphthyl, .beta.-naphthyl, .beta.-naphthyl, diphenylmethyl or ##STR64## R.sub.3 is --OR.sub.6, --NR.sub.6 R.sub.7 or ##STR65## R.sub.4 is hydrogen, lower alkyl or aryl lower alkyl;
• R.sub.5 is lower alkyl, hydroxylower alkyl, lower alkoxy lower alkyl;
• (di-lower alkyl) amino lower alkyl, Y.sub.1 --C.sub.6 H.sub.4 --lower alkyl, lower alkoxy, Y.sub.1 --C.sub.6 H.sub.4 --, naphthyl;
• R.sub.6 and R.sub.7 are independently hydrogen, lower alkyl or substituted lower alkyl wherein the substituents are selected from the group consisting of 1 or 2 hydroxy groups, 1 or 2 lower alkoxy groups, lower alkoxy lower alkoxy, halogeno, halogeno lower alkoxy, amino, mono- or di-lower alkylamino, aryl, or substituted aryl wherein the substituents on aryl are 1-3 substituents selected from the group consisting of lower alkyl, hydroxy, halogeno, lower alkoxy and amino;
• R.sub.8 is hydrogen, alkyl, carboxyalkyl, mercaptoalkyl, alkylthioalkyl, aminoalkyl, hydroxyalkyl, phenylalkyl, hydroxyphenylalkyl, guanidinoalkyl, or carbamoylalkyl;
• n is 0-3;
• A is ##STR66## X and X.sub.1 are independently a bond, --O--, --S--, or --CH.sub.2 --;
• Y, Y.sub.1 and Y.sub.2 are independently 1 to 3 substituents selected from the group consisting of hydrogen, lower alkyl, cyclolower alkyl, lower alkoxy, OH, F, Cl, Br, I, --CN, --CO.sub.2 H, --CO.sub.2 --lower alkyl, --CH.sub.2 NH.sub.2, --CONH.sub.2 and aryl;
• wherein aryl means mono-cyclic or fused ring bicyclic aromatic groups having 6 to 10 ring members or a pharmaceutically acceptable acid addition salt thereof.