Abstract: Improved chemical process for preparing the compounds of formula (I), wherein: R1 represents (C9-C12)alkyl; M represents hydrogen, &agr;-D-mannopyranosyl or 6-O-acetyl-&agr;-D-mannopyranosyl and Y represents an amino group of formula —NR2-alk1-(NR3-alk2)p-(NR4-alk3)q-W. One aspect of the invention refers to the preparation of the intermediate compound of formula (III) (which corresponds to the above compound of formula (I) wherein R1 and M are as above defined and Y is hydroxy), by reacting a compound of formula (II) (which corresponds to the above compound of formula (I) wherein R1 and M are as above defined and Y is hydroxymethyl), with a (C1-C4)alkanol in the presence of a concentrated mineral acid, using the same alkanol as the reaction solvent and submitting the obtained ester compound to a reductive process by adding an alkali metal borohndride into the same reaction mixture.

Abstract: The present invention is directed to novel antibiotic A 40926 derivatives characterized by having a carboxy, (C.sub.1 -C.sub.4) alkoxy-carbonyl, aminocarbonyl, (C.sub.1 -C.sub.4) alkylaminocarbonyl, di (C.sub.4 -C.sub.4)alkylaminocarbonyl or hydroxymethyl substituent on the N-acylaminoglucuronyl moiety and a hydroxy or a polyamine substituent in position 63 of the molecule. The compounds of the invention show high in vitro activity against glycopeptide resistant Enterococci and Staphylococci.