Three New Lanostane Triterpenoids from Inonotus obliquus

Abstract Three new lanostane‐type triterpenoids, inonotsulides A, B, and C (1–3, resp.) were isolated from the sclerotia of Inonotus obliquus (Pers.: Fr.) (Japanese name: Kabanoanatake; Russian name: Chaga). Their structures were determined to be (20R,24S)‐3β,25‐dihydroxylanost‐8‐en‐20,24‐olide (1), (20R,24R)‐3β,25‐dihydroxylanost‐8‐en‐20,24‐olide (2), and (20R,24S)‐3β,25‐dihydroxylanosta‐7,9(11)‐dien‐20,24‐olide (3) on the basis of chemical transformation, NMR spectroscopy including 1D and 2D (1H,1H‐COSY, NOESY, HMQC, HMBC), EI‐MS, and single‐crystal X‐ray analysis.