.alpha.-amino acid compounds

A compound selected from those of the formula (I):

• ##STR64## wherein:
• m is 0 or 1,
• each of X and Y, which may be identical or different, represents an alkyl group,
• A represents:
• a group ##STR65## and R.sub.1 represents:
• a hydrogen atom,
• an alkyl group,
• an alkyl group substituted by an amino group,
• an alkylthioalkyl group,
• an alkyl group substituted by an amino group that is itself substituted on the amino group by a group selected from tert-butoxycarbonyl, benzyloxycarbonyl and fluorenylmethoxycarbonyl,
• a phenyl or phenylalkyl group,
• a phenyl or phenylalkyl group substituted on the aromatic ring by an alkyl, hydroxy, alkoxy or trifluoromethyl group or by a halogen atom,
• and in that case--where A represents a --CH(R.sub.1)-- group:
• R.sub.2 represents a hydrogen atom or R.sub.2 forms with R.sub.1 and the N--CH grouping carrying them a monocyclic or bicyclic ring system, each ring containing 5 or 6 ring members and being saturated or unsaturated, and
• R.sub.3 represents:
• a hydrogen atom,
• a tert-butoxycarbonyl, benzyloxycarbonyl or fluorenylmethoxycarbonyl group,
• a benzoyl group,
• a benzoyl group substituted by an alkyl, alkoxy, hydroxy or trifluoromethyl group or by a halogen atom,
• a group ##STR66## wherein R.sub.A, R.sub.B and R.sub.C, which may be identical or different, represent a hydrogen atom or an alkyl group, or two groups from among R.sub.A, R.sub.B and R.sub.C form with the nitrogen atom carrying them a heterocyclic system selected from pyrrolidine, piperidine, azepine and morpholine, the third group from among R.sub.A, R.sub.B and R.sub.C then being either a hydrogen atom or an alkyl group,
• a group ##STR67## wherein R.sub.8 represents hydrogen, tert-butoxycarbonyl, benzyloxycarbonyl or fluorenylmethyloxycarbonyl, glycyl, glycyl itself substituted on the amino group by a group selected from tert-butoxycarbonyl, benzyloxycarbonyl and fluorenylmethoxycarbonyl and R.sub.10 represents hydrogen;
• alkyl;
• alkyl substituted by an amino group;
• alkyl substituted by an amino group that is itself substituted by a tert-butoxycarbonyl, benzyloxycarbonyl, fluorenylmethyloxycarbonyl;
• a phenyl group;
• or phenylalkyl group;
• or a phenyl or phenylalkyl group substituted on the phenyl ring by an alkyl, hydroxy, alkoxy or trifluoromethyl group or by a halogen atom,
• their isomers, epimers, enantiomers, diastereoisomers and also their addition salts with a pharmaceutically-acceptable acid or base,
• wherein alkyl and alkoxy are linear or branched groups containing 1 to 6 carbon atoms inclusive.