Effective protection of the N-sulfate of glucosamine derivatives with the 2,2,2-trichloroethyl group

The 2,2,2-trichloroethyl (TCE) group was utilized as the first protecting group for N-sulfates (chlorosulfuric acid TCE ester, Et3N, DMAP, DMF). Glycosylation with 3,4,6-tri-O-acetyl-N-trichloroethylsulfuryl-alpha-D-glucosaminosyl trichloroacetimidate provided the corresponding beta-glucosaminosides stereoselectively and in excellent yields. The TCE protection stayed stable under a variety of conditions for the manipulation of other protecting groups, and was readily removable with zinc in the presence of ammonium chloride in methanol. (c) 2008 Elsevier Ltd. All rights reserved.