4-DEOXY-ANALOGS OF P-NITROPHENYL BETA-D-GALACTOPYRANOSIDES FOR SPECIFICITY STUDY WITH BETA-GALACTOSIDASE FROM ESCHERICHIA-COLI

The synthesis is reported of p-nitrophenyl glycosides of D-galactose m odified at C-4 with azido- (5), amino- (6) group and fluorine (13). 3, 6-tri-O-benzoyl-4-deoxy-alpha-D-galactopyranosyl chloride and -benzoyl -4-deoxy-4-fluoro-alpha-D-galactopyranosyl bromide were coupled with p otassium p-nitrophenoxide in the presence of 18-crown-6 giving the cor responding p-nitrophenyl 4-azido- and 4-fluoro-4-deoxy-beta-D-galaccop yranoside derivatives. P-Nitrophenyl 4-amino-4-deoxy-beta-D-galactopyr anoside (6) was obtained by selective reduction of p-nitrophenyl 4-azi do-4-deoxy-beta-D-galactopyranoside (5) using 1,3-propane dithioltriet hylamine. These galactoside analogs were slowly hydrolyzed in the incr easing rate order of 5,6 and 13 by beta-galactosidase from Escherichia coli.