title: Synthesis of beta-D-GlcpNAc-(1-->3)-alpha-L-Rhap-(1-->2)-[beta-L-Xylp-(1-->4)]-alpha-L-Rhap-(1-->3)-alpha-L-Rhap, the repeating unit of the O-antigen produced by Pseudomonas solanacearum ICMP 7942.
abstract: An efficient synthesis of beta-D-GlcpNAc-(1-->3)-alpha-L-Rhap-(1-->2)-[beta-L-Xylp-(1-->4)]-alpha-L-Rhap-(1-->3)-alpha-L-Rhap, the repeating unit of the O-antigen produced by Pseudomonas solanacearum ICMP 7942 and its isomer beta-D-GlcpNAc-(1-->3)-alpha-L-Rhap-(1-->4)-[beta-L-Xylp-(1-->2)]-alpha-L-Rhap-(1-->3)-alpha-L-Rhap was achieved via sequential assembly of the building blocks, allyl 2,3-O-isopropylidene-alpha-L-rhamnopyranoside (2), allyl 3,4-O-isopropylidene-alpha-L-rhamnopyranoside (3), allyl 2,4-di-O-benzoyl-alpha-L-rhamnopyranoside (6), 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-beta-D-glucopyranosyl trichloroacetimidate (7), and 2,3,4-tri-O-benzoyl-beta-L-xylopyranosyl trichloroacetimidate (12). The process was carried out in a regio- and stereoselective manner using glycosyl trichloroacetimidates as donors and unprotected or partially protected rhamnopyranosides as acceptors in the presence of a catalytic amount of trimethylsilyl trifluoromethanesulfonate (TMSOTf).
authors.affiliation: Research Center for Eco-Environmental Sciences, Academia Sinica, Chinese Academy of Sciences, PO Box 2871, Beijing 100085, PR China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Zhang
authors.forename: Fanzuo
authors.initials: F
authors.lastname: Kong
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D007536:Isomerism; D019081:O Antigens / Q000737:chemistry*; D009844:Oligosaccharides / Q000138:chemical synthesis*; D011549:Pseudomonas / Q000737:chemistry*; D012210:Rhamnose / Q000737:chemistry
chemical_list: D019081:O Antigens; D009844:Oligosaccharides; C478181:beta-D-GlcpNAc-(1-3)-alpha-L-Rhap-(1-2)-(beta-L-Xylp-(1-4))-alpha-L-Rhap-(1-3)-alpha-L-Rhap; D012210:Rhamnose