DETERMINATION OF THE STRUCTURES OF VERSICOLACTONE B AND VERSICOLACTONE C IN THE ROOT OF ARISTOLOCHIA VERSICOLAR S.M.HWANG

Two novel sesquiterpene lactones with the trivial names as versicolactone B and versicolactone C, were isolated from the root of Aristolochia versicolar SM H wang. Versicolactone B, C₁₅H₂₀O₃, mp 135～136℃, is a germacranolide. Versicolactone C, C₁₅H₂₂O₄, mp 181～182℃, α_D³⁶-11.4°, is a new type of sesquiterpene lactone with hydroazulene skeletone. On the basis of UV, IR, ¹H NMR, ¹³C NMR, MS and chemical reactions the structure of versicolactone B was established as(Ⅰ), and versicolactone C as(Ⅱ). The figures of (Ⅲ) obtained by x-ray crystallography confirmed it The biogenesis of versicolactone C was guessed.