Three New Dimeric Benzofuran Derivatives from the Roots of Ligularia stenocephala MATSUM. et KOIDZ.

Abstract

Three new dimeric benzofuran derivatives, ligulacephalins A (1), B (2) and C (3), were isolated from the roots of Ligularia stenocephala MATSUM. ET KOIDZ. (Compositae) together with three known compounds, 5,6-dimethoxy-2-isopropenylbenzofuran (4), euparin (5) and (R)-(−)-hydroxytremetone (6). The structures of the new compounds were determined by spectroscopic evidence. The chiral HPLC analysis demonstrated that 1—3 occurred as a racemate. The absolute configurations of each enantiomer from 1—3 were elucidated on the basis of circular dichroism (CD) data.