摘要:
The invention concerns compounds of formula (I) wherein: X represents an oxygen or sulphur atom, or a CH2 or (1) group; R?1 and R2¿ represent a hydrogen atom, or a group such as defined in the description; A represents an alkylene chain as described in the description; B is such as defined in the description; R?3 and R4¿ represent a hydrogen atom or a group as defined in the description; D represents a benzene, pyridine, pyrazine, pyrimidine or pyridazine ring optionally substituted.