Process for preparing antibiotic L 17392 by catalytically hydrogenating a deglucoteicoplanin ester of formula (I), wherein A, B and Z represent hydrogen atoms, R represents benzyl or substituted benzyl, wherein the phenyl group is substituted with at least a substituent selected from chloro, bromo, fluoro, nitro, (C1-C3)alkyl, (C1-C3)alkoxy and the like, with the exclusion of the tri-nitro phenyl group, or acid addition salts thereof, to catalytic hydrogenolysis in the presence of a poisoned hydrogenation catalyst at a temperature from 10<o>C to 40<o>C and a pressure between ambient pressure and 5 atm, in an inert organic solvent preferably in the presence of a mineral acid.
