Synthesis of the trisaccharide portion of soyasaponin βg: evaluation of a new glucuronic acid acceptor
作者:Karen Plé
DOI:10.1016/s0008-6215(03)00195-2
日期:2003.7
The synthesis of the trisaccharide portion of soyasaponin betag 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-butyldimethyl-silyl-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. (C) 2003 Elsevier Science Ltd. All rights reserved.