Synthesis of a model compound related to an anti-ulcer pectic polysaccharide.
A stereocontrolled synthesis of the model compound for an anti-ulcer active polysaccharide (Bupleuran 2IIc) is described. Glycosidation of the disaccharide acceptor, 2-O-acetyl-3-O-benzyl-4-O-(p-methoxybenzyl)-alpha-L-rhamnopyranosyl-(1-- >4)-2,3,6-tri-O-benzyl-alpha-D-galactopyranosyl trichloroacetimidate, with the disaccharide receptor, allyl 3,4-di-O-benzyl-alpha-L-rhamnopyranosyl-(1-->4)-2,3,6-tri-O-benzyl-beta- D-galactopyranoside, using silver triflate (AgOTf) as a promoter gave the desired tetrasaccharide derivative, which was transformed into the acidic tetrasaccharide, corresponding to a segment of the rhamnogalacturonan (Bupleuran 2IIc) polysaccharide, propyl alpha-L-Rha-(1-->4)-alpha-D-GalA-(1-->2)-alpha-L-Rha-(1-->4)-beta-D-GalA , via removal of the corresponding ether and ester protecting groups, followed by oxidation.
Maruyama
M
M
Koritsu College of Pharmacy, Tokyo, Japan.
Takeda
T
T
Shimizu
N
N
Hada
N
N
Yamada
H
H
D000897:Anti-Ulcer Agents / Q000138:chemical synthesis* / Q000737:chemistry; D002240:Carbohydrate Sequence; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008969:Molecular Sequence Data; D010368:Pectins / Q000138:chemical synthesis* / Q000737:chemistry
D000897:Anti-Ulcer Agents; C073829:Bupleuran 2IIc; D010368:Pectins