A compound of the structural formula I, a pharmaceutically acceptable salt,prodrug or derivative thereof,characterized in that R1 is selected from H, a linear or branched (C1-C5)alkyl group and a COR4 group； R2 is selected from H, a linear orbranched (C1-C5) alkyl group and a COR5 group； R3 is selected from H, a linearor branched (C1-C5) alkyl group, a linear orbranched (C1-C5)- O-alkyl group, a cycloalkyl of (C5-C6) carbon atoms, an arylgroup, and an aryl (C1-C5) alkyl group wherein thearyl group can be an unsubstituted aryl or an aryl substituted with one ormore R6 groups and an NHCOR5 group, or the R2 and R3groups together with N may form a substituted or unsubstituted piperidine,morpholine or piperazine group； R4 is selected from Hand a (C1-C5) alkyl group； R5 is selected from an unsubstituted aryl group oran aryl group substituted with one or more R6, linear orbranched (C1-C5) alkyl or pyridyne groups and a pyridine group； R6 is selectedfrom (C1-C5) alkyl groups, halogen and nitro,provided that R1, R2 and R3 are not H atoms at the same time. The compoundspresent antibacterial activity. Process for theirpreparation and pharmaceutical compositions comprising them are alsodisclosed.
