Structures of novel sesquiterpenes from the pericarps of Illicium merrillianum

Five new sesquiterpenes, named merrillianone (1), cyclomerrillianolide (2), merrillianolide (3), 1 alpha-hydroxy-3-deoxypseudoanisatin (4) and 7-O-ace tylanislactone B (5), were isolated from the pericarps of Illicium merrilli anum, a species indigenous to southwestern China and Burma. Their structure s were elucidated based on spectroscopic and chemical data, The structure o f 1 was confirmed by X-ray crystallographic analysis of its acetylated deri vative la to consist of a novel cagelike acetal and hemiacetal structure. T he NMR data for compounds 2 and 3, which could not be separated due to an e quilibrium mixture of keto and hemiacetal forms, were unambiguously assigne d, respectively.