Mercaptoacyl derivatives of 3-substituted proline derivatives

A compound of the formula ##STR32## and physiologically acceptable basic salts thereof;

• X is SH, lower alkoxy, lower alkylthio, hydroxy, phenylthio, phenyloxy, biphenylthio, biphenyloxy, 1-naphthylthio, 1-naphthyloxy, 2-naphthylthio, 2-naphthyloxy, substituted phenylthio or substituted phenyloxy wherein the substituents on the above phenyl groups are one or two halogens, hydroxy, lower alkyl, lower alkoxy, lower alkylthio, cyano or nitro groups;
• R is hydrogen or lower alkyl;
• R.sub.1 is hydrogen, hydroxy, halogen or lower alkoxy, with the proviso that when R.sub.1 is hydrogen, X can only be SH, and R.sub.1 and X cannot both be hydroxy;
• R.sub.2 is hydrogen, lower alkyl or trifluoromethyl;
• R.sub.3 is hydrogen, ##STR33## R.sub.4 is lower alkyl or phenyl;
• and n is 0, 1 or 2.