A daunorubicin β-galactoside prodrug for use in conjunction with gene directed enzyme prodrug therapy

N-[4-(β-d-Galactopyranosyl)-3-nitrobenzyloxycarbonyl]daunomycin was synthesized as a neutral prodrug of daunomycin. Although stable in 0.05 M phosphate buffer, pH 7.4 at 37°C, it was rapidly converted to daunomycin and 3-nitro-4-hydroxybenzyl alcohol under the same conditions in the presence of E. coli β-galactosidase.