| abstract |
Compounds of formula (I): n n n wherein: n X represents an oxygen atom or a sulphur atom or a group CH 2 or n n n R 1 and R 2 represent a hydrogen atom, or a group as defined in the description, n A represents an alkylene chain as described in the description, n B is as defined in the description, n R 3 and R 4 represent a hydrogen atom or a group as defined in the description, n D represents an optionally substituted benzene, optionally substituted pyrazine, optionally substituted pyrimidine or optionally substituted pyridazine nucleus. |