New pseudoanisatin-like sesquiterpene lactones from the bark of Illicium dunnianum

Abstract

Three new sesquiterpene lactones, 6-deoxypseudoanisatin (4), dunnianin (5), and 6-deoxydunnianin (6), have been isolated from the bark of Illicium dunnianum. The structure elucidation of these constituents is based on a detailed study of their high-field ¹H and ¹³C n.m.r. spectra in comparison with those of pseudoanisatin (1). Two-dimensional homonuclear and heteronuclear correlation experiments were extensively used in the assignment of the n.m.r. spectra.