The present invention relates to derivatives of formula (I)in which R1 and R2, identical or different, represent a hydrogen atom or a linear or branched C1-4 alkyl radical provided that one of R1 and R2 is different from a hydrogen atom R3 represents a bicyclic group of general formula (II):X represents O or -CH2- or -(CH2)2- in the form of a free base, of an hydrate or of a solvate.