Synthesis of the two monomethyl esters of the disaccharide 4- O-α- d-galacturonosyl- d-galacturonic acid and of precursors for the preparation of higher oligomers methyl uronated in definite sequences

• Published in: Carbohydrate research 1998-12, Vol.314 (3), p.189-199
• Main Authors: Magaud, Didier, Grandjean, Cyrille, Doutheau, Alain, Anker, Daniel, Shevchik, Vladimir, Cotte-Pattat, Nicole, Robert-Baudouy, Janine
• Format: Article
• Language: English
• Subjects: Chemical Sciences; d-Galacturonic acid esters; Esters - chemical synthesis; Glycosylation; Hexuronic Acids - chemical synthesis; Models, Chemical; Organic chemistry; Pectins; Thioglycosides
• ISSN: 0008-6215; 1873-426X; 0008-6215
• DOI: 10.1016/S0008-6215(98)00312-7

Methyl (α- d-galactopyranosyluronic acid)-(1→4)- d-galactopyranuronate and methyl α- d-galactopyranosyluronate-(1→4)- d-galactopyranuronic acid have been synthesized by coupling methyl (benzyl 2,3-di- O-benzyl-β- d-galactopyranosid)uronate ( 3) or benzyl (benzyl 2,3-di- O-benzyl-β- d-galactopyranosid)uronate ( 4) with benzyl (phenyl 2,3,4-tri- O-benzyl-1-thio-β- d-galactopyranosid)uronate and methyl (phenyl 2,3,4-tri- O-benzyl-1-thio-β- d-galactopyranosid)uronate, respectively, using N-iodosuccinimide and trifluoromethanesulphonic acid as promoters, followed by removal of the benzyl groups. The 4′-OH unprotected dimers benzyl (methyl 2,3-di- O-benzyl-α- d-galactopyranosyluronate)-(1→4)-(benzyl 2,3-di- O-benzyl-β- d-galactopyranosid)uronate and methyl (benzyl 2,3-di- O-benzyl-α- d-galactopyranosyluronate)-(1→4)-(benzyl 2,3-di- O-benzyl-β- d-galactopyranosid)uronate were prepared from methyl (phenyl 2,3-di- O-benzyl-1-thio-4- O-trimethylsilyl-β- d-galactopyranosid)uronate and benzyl (phenyl 2,3-di- O-benzyl-1-thio-4- O-trimethylsilyl-β- d-galactopyranosid)uronate and acceptors 4 or 3, respectively. These compounds have been designed to serve as precursors for the preparation of higher-membered d-galacturonic acid oligomers methyl esterified in definite positions.