acetylation

Reference Information

Synthesis of β-image-glucose oligosaccharides from Phytophthora parasitica
Youlin Zeng and Fanzuo Kong
Carbohydrate Research Volume 338, Issue 22, 31 October 2003, Pages 2359-2366


Abstract
The glucohexaose, b-D-Glcp-(10/3)-[b-D-Glcp-(10/3)-b-D-Glcp-(10/3)-b-D-Glcp-(10/6)]-b-D-Glcp-(10/3)-D-Glcp, was synthesized as its allyl glycoside via 3 /3 strategy. The trisaccharide donor, 2,3,4,6-tetra-O-benzoyl-b-D-glucopyranosyl-(10/3)-2,4,6-tri-
O-acetyl-b-D-glucopyranosyl-(10/3)-2,4,6-tri-O-acetyl-a-D-glucopyranosyl trichloroacetimidate (11), was obtained by 3-selective coupling of isopropyl 4,6-O-benzylidene-1-thio-b-D-glucopyranoside (2) with 2,3,4,6-tetra-O-benzoyl-b-D-glucopyranosyl-(10/3)-2- O-acetyl-4,6-O-benzylidene-a-D-glucopyranosyl trichloroacetimidate (6), followed by hydrolysis, acetylation, dethiolation, and
trichloroacetimidation. Meanwhile, the trisaccharide acceptor, allyl 2,3,4,6-tetra-O-benzoyl-b-D-glucopyranosyl-(10/3)-2-O-acetylb-
D-glucopyranosyl-(10/3)-4,6-di-O-acetyl-2-O-benzoyl-a-D-glucopyranoside (14), was prepared by coupling of allyl 4,6-di-Oacetyl- 2-O-benzoyl-a-D-glucopyranoside (12) with 6, followed by debenzylidenation. Condensation of 14 with 11, followed by deacylation, gave the target hexaoside. A b-(10/3)-linked tetrasaccharide 29 was also synthesized with methyl 2-O-benzoyl-4,6-Obenzylidene-
b-D-glucopyranosyl-(10/3)-2,4,6-tri-O-acetyl-b-D-glucopyranoside (25) as the acceptor and acylated b-(10/3)-linked disaccharide 21 as the donor.

Keywords[/o]-D-Glucans; Trichloroacetimidates; Regio- and stereoselective synthesis

[Edited on 25-9-2007 by solo]

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