Substituted imino diacids, their preparation and pharmaceutical compositions which contain them

Compounds having the general formula:

• ##STR20## wherein the ring A is saturated and n=1,
• R.sub.1 represents a lower alkyl group having from 1 to 4 carbon atoms which can carry an amino group,
• R.sub.2 represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms,
• R.sub.3 represents a straight or branched alkyl group, a monoor di-cycloalkylalkyl group having no more than a total of 9 carbon atoms, or a substituted alkyl group of the formula:
• ##STR21## with R.sub.4 =H, a lower alkyl (C.sub.1 to C.sub.4) or a cycloalkyl (C.sub.3 to C.sub.6) group,
• R.sub.5 32 H, a lower alkyl (C.sub.1 to C.sub.4), a cycloalkyl (C.sub.3 to C.sub.6) or an alkoxycarbonyl group,
• Y=S or >N-Q where Q=H, or an acetyl or benzyloxycarbonyl group,
• and
• p=1 or 2, and
• a=0 or 1
• in their racemic form or as optical isomers, and the salts thereof obtained with a therapeutically compatible inorganic or organic base, or their addition salts obtained with a pharmaceutically compatible inorganic or organic acid.