Sesquiterpenoids and Lactone Derivatives from Ligularia dentata

✍ Scribed by Hitomi Baba; Yasunori Yaoita; Masao Kikuchi

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: German
• Weight: 128 KB
• Volume: 90
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.200790086

✦ Synopsis

Abstract

Seven new compounds were isolated from the roots of Ligularia dentata, including five bisabolane‐type sesquiterpenoids (bisabolane=1‐(1,5‐dimethylhexyl)‐4‐methylcyclohexane), namely (8__β__,10__α__)‐8‐(angeloyloxy)‐5,10‐epoxybisabola‐1,3,5,7(14)‐tetraene‐2,4,11‐triol (1), (8__β__,10__α__)‐8‐(angeloyloxy)‐5,10‐epoxythiazolo[5,4‐a]bisabola‐1,3,5,7(14)‐tetraene‐4,11‐diol (2), (1__α__,2__α__,3__β__,5__α__,6__β__)‐1,5,8‐tris(angeloyloxy)‐10,11‐epoxy‐2,3‐dihydroxybisabol‐7(14)‐en‐4‐one (3), (1__α__,2__α__,3__β__,5__α__,6__β__)‐2,5,8‐tris(angeloyloxy)‐10,11‐epoxy‐1,3‐dihydroxybisabol‐7(14)‐en‐4‐one (4), and (1__α__,2__β__,3__β__,5__α__,6__β__)‐1,8‐bis(angeloyloxy)‐2,3‐epoxy‐5,10‐dihydroxy‐11‐methoxybisabol‐7(14)‐en‐4‐one (5) (angeloyloxy=[(2__Z__)‐2‐methyl‐1‐oxobut‐2‐enyl]oxy), and two lactone derivatives, (2__α__,3__β__,5__α__)‐2‐(acetyloxy)‐9‐methoxy‐5‐(methoxycarbonyl)‐2,3‐dimethylheptano‐5‐lactone (6), and (2__β__,4__β__)‐2‐ethyl‐5‐hydroxy‐5‐(methoxycarbonyl)‐4,5‐dimethylpentano‐4‐lactone (7) (α/β denote relative configurations), together with (2__E__,4__R__,5__S__)‐2‐ethylidene‐5‐(methoxycarbonyl)‐4‐methylhexano‐5‐lactone (8), a known synthetic compound. Compound 2 is the first sesquiterpenoid derivative containing the uncommon benzothiazole moiety. The structures of 1–8 were established by spectroscopic methods, especially 2D‐NMR and MS analyses.