The Structure of Acacetin-trisaccharide, a Component of Robinia pseudoacaciat

Abstract

The structure of acacetin-7-trioside [1], a component of the leaves of Robinia pseudoacacia, was elucidated. Upon hydrolysis of [1] with hydrochloric acid, acacetin, D-glucose, L-rhamnose, and D-xylose were obtained, while upon partial hydrolysis of [1] with 10% acetic acid, linarin (acacetin-7-8-rutinoside) and D-xylose were formed as main products. Upon methylation of [1] with dimethyl sulfate, nonamethylate [2] was obtained; upon hydrolysis of this with acid, 5, 4'-dimethylapigenin, 2, 3, 4-tri-O-methyl-L-rhmnose, 2, 3, 4-tri-O-methyl-D-xylose, and 3, 4-di-O-methyl-D-glucose were formed. In terms of NMR spectrum, Cl linkage of D-xyloside was confirmed to be β-bond.
On the basis of the above results the structure of [1] is 7-0- [O-α-L-rhamnopyranosyl0-[8- D-xylopyranosyl- (1-2) ]-8-D-glucopyranosyl] acacetin.