Abstract: The present invention relates to a compound of formula (I) or a pharmaceutically acceptable salt, a stereoisomer or a mixture in all proportions of stereoisomers thereof, in particular a mixture of enantiomers, such as a racemic mixture, wherein R represents a (C1-C6)alkyl or (C1-C6)alkenyl group, optionally substituted by one or more groups chosen among an halogen atom, ORa, SRb, NRcRd, PO(ORe)(ORf), CO2Rg, SO2Rh SO3R1, P0(0H)(CH(0H)Rk), CN, N3 and NH—C(?NH)NH2, with Ra, Rb, Rc and Rd, representing, independently of each other, an hydrogen atom, a (C1-C6)alkyl group or a —CO—(C1-C6)alkyl group, Re, Rf, Rg, Rh and R1 representing, independently of each other, an hydrogen atom or a (C1-C6)alkyl group, and Rk representing an aryl or heteroaryl group, said group being optionally substituted by one or more groups selected from an halogen atom and NO2, as well as to the use thereof and to a process for preparing such a compound, to a pharmaceutical composition containing it and to synthesis intermediates.