This invention concerns compounds with the formula: in which: R1&boxHOH or NH2 OR2, OR3, OR4 and OR5 are alcohol, ether, ester, carbonate, carbamate, sulphonate or sulphamate groups and if R5&boxHH if R2&boxHR3&boxHR4, then R2, R3 and R4&neH if R2&boxHH, then R3&neH and R4&neH if R3&boxHH, then R2&neH and R4&neH if R4&boxHH, then R2&neH and R3&neH if R5&neH if R2=H, then R3&neH and R4&neH if R3&boxHH, then R2&neH and R4&neH if R4&boxHH, then R2&neH and R3&neH, their use as antibiotic agents and the process for synthesizing them.