Abstract: The invention concerns a compound of formula (I), Formula (I), R, R1 and R2 are independently selected form the group consisting of: —a hydrogen atom, —a halogen atom, —an alkyl group, linear, cyclic or branched, saturated or unsaturated, possibly substituted, comprising from 1 to 10 carbon atoms, —an acyl group comprising from 1 to 10 carbon atoms, —a carboxyl group, —an amido group comprising from 1 to 10 carbon atoms, and —an imino group, possibly substituted by an alkyl group, linear, cyclic or branched, saturated or unsaturated, and wherein R3, R4, R5 and R6 are independently selected form the group consisting of: —a hydrogen atom, —a halogen atom, —a hydroxyl group, —an alkyl group, linear, cyclic or branched, saturated or unsaturated, possibly substituted, comprising from 1 to 10 carbon atoms, —an alkoxy group comprising from 1 to 10 carbon atoms, —an acyl group comprising from 1 to 10 carbon atoms, —a carbonate group from 1 to 10 carbon atoms, —a carboxyl group, and —a cyano group.