Synthesis of 2-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-D-mannose, and its interaction with D-mannose-specific lectins

Condensation of 3, 4:5, 6-di-O-isopropylidene-D-mannose dimethyl acetal with 2-methyl-(3, 4, 6-tri-O-acetyl-1, 2-dideoxy-alpha-D-glucopyrano)-[2', 1':4, 5]-2- oxazoline in the presence of a catalytic amount of p-toluenesulfonic acid afforded crystalline 2-O-(2-acetamido-3, 4, 6-tri-O-acetyl-2-deoxy-beta-D-glucopyranosyl)-3, 4:5, 6-di-O-isopropylidene-D-mannose dimethyl acetal (3) in 25 percent yield. Catalytic deacetylation of 3 with sodium methoxide, followed by hydrolysis with dilute sulfuric acid, gave 2-O-(2-acetamido-2-deoxy-alpha-D-glucopyranosyl)-D-mannose (4). Treatment of 3 with boiling 0.5 percent methanolic hydrogen chloride under reflux gave methyl 2-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-alpha-D-mannopyranoside (5) and methyl 2-o-2-acetamido-2-deoxy-beta-D-glucopyranosyl)-alpha-D-mannofuranoside (6). The inhibitoryactivities of 4, 5, and 6 against the hemagglutinating and mitogenic activities of Lens culinaris and Pisum sativum lectins and concanavalin A were assayed. From the results of these hapten inhibition studies, subtle differences of specificity between these D-mannose-specific lectins were confirmed.