Chemical Studies on the Constituents of Polygonum nodosum

抄録

A new cyclobutane derivative, which may be formed from dehydrokawain by [2+2] cycloaddition, named compound B (8a), mp 226-227°C, C₂₈H₂₄O₆, and a new flavanonol, named compound C (10a), mp 142-143°C, C₁₇H₁₄O₆, together with pinobanksin (1a), taxifolin (2a), quercetin-3β-D-glucopyranoside 2"-gallate (3), pinosylvin (4a), methyl gallate (5a), dehydrokawain (6) and compound A (7a) were isolated from Polygonum nodosum (Polygonaceae). The structures of the new compounds, 8a and 10a, were established to be rel-1, trans-3-bis-(4-methoxy-2-oxopyran-6-yl)-cis-2, trans-4-diphenyl cyclobutane and (2R, 3R)-3-hydroxy-5-methoxy-6, 7-methylenedioxy-flavanone, respectively, on the basis of physicochemical evidence. The structure of 7a was also established to be rel-(1R, 6S, 7S, 8S)-5-methoxy-7-phenyl-8-(4-methoxy-2-oxopyran-6-yl)-1-(E) styryl-2-oxabicyclo-[4, 2, 0]-oct-4-en-3-one and this compound was found to be identical with aniba-dimer-A.