Synthesis of the trisaccharide portion of soyasaponin beta g: evaluation of a new glucuronic acid acceptor.
The synthesis of the trisaccharide portion of soyasaponin beta g was successfully achieved using a new glucuronic acid acceptor: methyl 1-O-allyl-3,4-di-O-methoxymethyl-beta-D-glucuronate (9). This compound and methyl 1-O-allyl-3,4-di-O-tert-butyldimethylsilyl-beta-D-glucuronate (8) were both prepared from glucuronolactone via a glycal intermediate. The former compound 9 was successfully coupled to ethyl 2-O-benzoyl-3,4,6-tri-O-benzyl-1-thio-beta-D-galactopyranoside (13) in excellent yield. Synthesis of the protected trisaccharide was then completed by the addition of a suitably protected rhamnose derivative to the disaccharide portion. The reactivity of the glucuronic acid derivative 9 was also explored with trichloroacetimidate and fluoride donors.
Plé
Karen
K
Laboratoire de Pharmacognosie, Université de Reims Champagne-Ardenne, CNRS UMR 6013, CPCBAI, Bât. 18, Moulin de la Housse, BP 1039, F-51687 Reims, France. karen.ple@univ-reims.fr
D002240:Carbohydrate Sequence; D005965:Glucuronates / Q000737:chemistry*; D008956:Models, Chemical; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009828:Oleanolic Acid / Q000031:analogs & derivatives* / Q000737:chemistry*; D012503:Saponins / Q000737:chemistry*; D014312:Trisaccharides / Q000138:chemical synthesis*
D005965:Glucuronates; D012503:Saponins; D014312:Trisaccharides; C089346:soyasaponin beta g; D009828:Oleanolic Acid