Abstract
Selective tosylation of 1, 6-anhydro-4', 6'-O-benzylidene-β-maltose (1) with 4.2 molar equivalents of tosyl chloride (TsCl) in pyridine at 0°yielded 5 tosylates, which were designated 2 to 6 in order of decreasing Rf value on thin-layer chromatography. After column chromatography on silica gel, compounds 2-6 were separated and identified as the 2, 2', 3, 3'-tetratosylate (2, 2%), 2, 2', 3-tritosylate (3, 15%), 2, 2', 3'-tritosylate (4, 10%), 2, 2'-ditosylate (5, 67.7%), and 2'-monotosylate (6, 1.7%), respectively. Selective tosylation of 5 with 8 molar equivalents of TsCl in pyridine at 0°afforded 2 (9.3%), 3 (17.3%), and 4 (24.7%), together with 5 (39.3%). Compound 5, the major product of the selective tosylation of 1, is a valuable intermediate in the chemical modification of maltose.
