Facile synthesis of the sugar cores from phenylpropanoid glycosides.
Allyl 2-O-benzoyl-4,6-O-benzylidene-alpha-D-glucopyranoside (3), obtained by selective benzoylation of allyl 4,6-O-benzylidene-alpha-D-glucopyranoside (2) with benzoyl chloride-imidazole in anhydrous chloroform, reacted with 2, 3, 4-tri-O-benzoyl-alpha-L-rhamnopyranosyl bromide to give a disaccharide derivative (4), and an important intermediate (5) was obtained by cleavage of its acetal. Treatment of 5 with a series of glycopyranosyl bromides, protected by acetyl or benzoyl groups in benzene-nitromethane in the presence of Hg(CN)2 as a catalyst afforded four trisaccharides (6-9). The disaccharide (5) and trisaccharides (6-9) constitute the sugar cores of phenylpropanoid glycosides. A new glycosyl anomeric leaving group, trichloroacetoxy, was employed to prepare the disaccharide (4) and trisaccharides residue (8) efficiently and with high stereoselectivity.
Li
Z J
ZJ
School of Pharmaceutical Sciences, Beijing Medical University, China.
Huang
H Q
HQ
Cai
M S
MS
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002934:Cinnamates; D004187:Disaccharides / Q000138:chemical synthesis / Q000737:chemistry; D006027:Glycosides; D007202:Indicators and Reagents; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D013329:Structure-Activity Relationship; D014312:Trisaccharides / Q000138:chemical synthesis / Q000737:chemistry
D002934:Cinnamates; D004187:Disaccharides; D006027:Glycosides; D007202:Indicators and Reagents; D009844:Oligosaccharides; D014312:Trisaccharides