Novel diterpenoids from the Indian Ocean soft coral Sarcophyton elegans

Chemical examination of the soft coral species Sarcophyton elegans collected from the Havelock Island of the Andaman and Nicobar group of Islands of the Indian Ocean resulted in the isolation of four novel diterpenoids, sarcophytin (1), 7-dehydrosarcophytin (2), Δ⁷⁽¹⁵⁾-dehydrosarcophytin (3) and isosarcophytin (4) along with some known compounds. The structures of the new diterpenoids were established by the help of their physical and spectral data including X-ray analysis on sarcophytin (1). The known compounds are Δ⁹⁽¹⁵⁾-africanene (5), methyl arachidonate (6), (24S)-24-methylcholestane-3β,25-diol (7), batyl alcohol (8), (24S)-24-methylcholestane-1β,3β,5α,6β,25-pentol (10), its 25-monoacetate (9), three monohydroxy sterols 4α,24-dimethylcholestan-3β-ol (11a), 4α,23ξ,24ξ-trimethylcholestan-3β-ol (11b) and 23ξ-ethyl-4α,24ξ-dimethylcholestan-3β-ol (11c) as a mixture.