Glycosidases. Ligands for affinity chromatography:. III. Syntheses of p-aminophenyl 2-acetamido-2-deoxy-1-thio-β-D-glucopyranoside and -galactopyranoside

p-Aminophenyl 2-acetamido-2-deoxy-1-thio-β-D-glucopyranoside and -galactopyranoside were synthesized for use as ligands in the purification of 2-acetamido-2-deoxy-β-D-glucosidase, from Aspergillus niger and Phaseolus vulgaris, by affinity chromatography. The condensation of 2-acetamido-1,3,4,6-tetra-O-acetyl-2-deoxy-α-D-glucose and -β-D-galactose with p-nitrothiophenol in the presence of zinc chloride afforded p-nitrophenyl 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-1-thio-β-D-glucopyranoside and -galactopyranoside, respectively. The former was also obtained by the reaction of 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-α-D-glucopyranosyl chloride with p-nitrothiophenol in the presence of potassium hydroxide. O-Deacetylation followed by reduction with hydrogen over palladium on barium sulfate gave the p-aminophenyl 2-acetamido-2-deoxy-1-thio-β-D-glucopyranoside and -galactopyranoside. Inhibition constants (K_i) of the p-nitrophenyl and p-aminophenyl 2-acetamido-2-deoxy-1-thio-β-D-glucosides and -galactosides for A. niger 2-acetamido-2-deoxy-β-D-glucosidase were determined by using p-nitrophenyl 2-acetamido-2-deoxy-β-D glucopyranoside and -galactopyranoside as substrates.