A pharmaceutically acceptable salt, prodrug or derivative compound of the formula I, wherein R1 is selected from H, a (C1-C5) alkyl group and a COR4 group; R2 is selected from H, a (C1-C5) alkyl group and a COR5 group; R3 is selected from H, a (C1-C5) alkyl group, a (C1-C5)-O-alkyl group, a cycloalkyl of (C5-C6) carbon atoms, an aryl group, and an aryl (C1-C5) alkyl group wherein the aryl group can be an unsubstituted aryl or substituted with one or more R6 groups and an NHCOR5 group, or the R2 and R3 groups together with N may form a piperidine, morpholine or piperazine group; R4 is selected from H and a (C1-C5)alkyl group; R5 is selected from an aryl group unsubstituted or substituted with one or more R6, linear or branched(C1-C5) alkyl or pyridyne groups and a pyridine group; R6 is selected from (C1-C5)alkyl groups, halogen and nitro.