Synthesis of chitotetraose and chitohexaose based on dimethylmaleoyl protection

摘要

tert-Butyldimethylsilyl 3,6-di-0-benzyl-2-deoxy-2-dimethylmaleimido-#beta#-D-glucopyranoside was readily trans- formed into the disaccharide glycosyl donor, 3,4,6-tri-0-acetyl-2-deoxy-2-dimethylmaleimido#alpha# -#beta#-D-glucopyranosyl- (1-+4)-3,6-di-0-benzyl-2-deoxy-2-dimethylmaleimido-(X/~-D-glucopyranosyl trichloroacetimidate, and the disaccharide glycosyl acceptor, tert -butyldimethylsilyl 3,6-di-0-benzyl-2-deoxy-2-dimethylmaleimido-#beta#-D-glucopyra- nosyl-(1-+4)-3,6-di-0-benzyl-2-deoxy-2-dimethylmaleimido-#beta#-D-glucopyranoside. A TMSOTf-catalysed coupling of the acceptor with the donor afforded the respective tetrasaccharide derivative, which can be transformed to chitotetraose. tert -Butyldimethylsilyl 3, 6-di -0- benzyl- 2-deoxy-2-dimethylmaleimido-4- 0- phenoxyacetyl-#beta#- D-glucopy - ranosyl-(l -+ 4)-3,6-di-0-benzyl-2-deoxy-2-dimethylmaleimido-#beta#-D-g1ucopyranoside was converted into donor 3,6-di- 0- benzyl-2-deoxy-2-dimethylmaleimido-4- O-phenoxyacetyl-#beta#-D-glucopyranosyl-(l -.4)- 3,6-di -0- benzyl- 2-deoxy-2- dimethylmaleimido-#beta#-D-glucopyranosyl trichloroacetimidate. Its coupling with benzyl 3,6-di-0-benzyl-2-deoxy-2- dimethylmaleimido-#beta#-D- glucopyranosyl-( 1 -.4)- 3, 6-di -0- benzyl- 2-deoxy -2-dimethylmaleimido-#beta#-D- glucopyranoside, followed by dephenoxyacetylation, gave benzyl 3,6-di-0-benzyl-2-deoxy-2-dimethylmaleimido-#beta#-D-glucopyranosyl- (1-+4)-3,6-di- 0- benzyl-2-deoxy-2-dimethylmaleimido-#beta#-D-glucopyranosyl-(l -.4)- 3,6-di- 0- benzyl-2-deoxy-2- dimethylmaleimido-#beta#-D-glucopyranosyl-( 1 -.4)- 3, 6-di -0- benzyl- 2-deoxy -2-dimethylmaleimido-#beta#-D- glucopyranoside, whose glycosylation furnished, after replacement of the DMM-group by the acetyl moiety and subsequent deprotection, chitohexaose. @ 2001 Elsevier Science Ltd. All rights reserved.