| abstract |
The invention relates to the compounds of formula (I): (see formula I) wherein R1 and R2 together form the following carbon chain: (see formula II) in which : R3 represents a hydrogen atom or an alkyl group, ~ R4 represents a hydrogen atom, an alkyl group, aryl, heteroaryl, 3,4-dioxocyclobutenyl, alkylcarbonyl, cycloalkylcarbonyl, heterocycloalkylcarbonyl, benzoyl, arylsulfonyl or heteroarylsulfonyl, each of these groups being optionally substituted, ~ R3 and R4 together with the nitrogen atom which carries them a cycle comprising from 5 to 8 members, the ring thus formed being optionally substituted. |