Studies on the constituents of the rhizomes of Petrasites japonicus MAXIM. Structures of New Dinor-eremophilane Derivatives and New Eremophilenolides from the Rhizomes of Petasites japonicus MAXIM.

Abstract

Four new dinor-eremophilane derivatives with a rare skeleton, eremopetasinorone A (1), eremopetasinorone B (2), eremopetasinorol (3) and epoxyeremopetasinorol (4), and three new eremophilenolides, eremosulphoxinolide A (5), eremosulphoxinolide B (6) and 3β, 8α-dihydroxy-6β-methoxyeremophil-7(11)-en-12, 8β-olide (7), have been isolated from the dried fhizomes of Petasites japonicus MAXIM. (Compositae) with 2β-hydroxyeremophil-7(11)-en-12, 8α-olide (8), a known synthetic compound. The structures of these compounds were elucidated on the basis of spectral data and chemical transformation.