| abstract |
Process for the preparation of the compounds of formula I: in which : R₁ represents a hydrogen atom or an alkyl radical comprising from 1 to 3 carbon atoms, R represents a hydrogen atom, an alkyl radical comprising from 1 to 4 carbon atoms, or an acyl radical - CO - R ′ in which R ′ represents an alkyl radical comprising from 1 to 4 carbon atoms, X represents O or H₂, of their isomers, as well as their addition salts with a pharmaceutically acceptable acid or base. |