New sulfonyl derivatives of alpha-amino acids, their process for the preparation and pharmaceutical compositions containing them

A compound of formula (I): (CF DRAWING IN BOPI) wherein: (CF DRAWING IN BOPI) represents a nitrogen-containing heterocyclic 5-membered optionally substituted, - R1 represents a hydrogen atom or an alkyl, acyl, prolyl, alanyl, or histidylprolyle phenylalanylprolyle, - Ak represents an alkylene or heteroalkylene chain, X - represents a single bond or a phenylene group optionally substituted, - R2 represents an optionally substituted alkyl, cycloalkyl (C3-C7), or NR2A-R2b wherein R2a and R2b, which are identical or different, each represent an alkyl group, or together form, with the nitrogen atom which carries them, a nitrogen heterocycle, - Y represents a group (CF DRAWING iN BOPI) wherein R3 and R4, identical or different, each represent a hydrogen atom or an alkyl group, or R3 and R4 together with the atoms carrying them, an imidazolidine ring or dihy drobenzimidazole, its optical isomers and its addition salts with a pharmaceutically acceptable acid. Medications.