New carbohydrate derivatives of norfloxacin

New classes of sugar derivatives of the antibacterial drug norfloxacin (1) were synthesized by substituting the N-4′ of the piperazinyl moiety of the molecule. Direct coupling with gluco- and galactopyranosyl units afforded glycosylamines 2-5. Introduction of urea or thiourea linkage between glycosyl and norfloxacin units was produced with the corresponding glycosyl isocyanates or isothiocyanates. For the synthesis of unprotected sugar urea compounds, a new approach was applied by using 1,2-N, O-carbonyl-β-D-glycopyranoses. Hydrazinocarbonyl-methyl- and -propyl spacers also were found appropriate for linking norfloxacin with sugar units.