Two new terpenoid derivatives from a new soft coral species of the Nephthea genus of the Indian Ocean

Chemical examination of a new soft coral species of the Nephthea genus of the Indian Ocean furnishes a new sesquiterpenoid and a new diterpenoid along with some sesquiterpenes and steroids. The structure of the new sesquiterpenoid has been established as 1S, 3R, 4S, 5S, 7S-3,4-epoxy guaia-Delta(10(12))-ene 3 and that of a new monohydroxy diterpenoid as 4 by a study of their physical and spectral (H-1, C-13, 2D NMR, IR, UV and mass) data. Other known compounds isolated are Delta(9(15))- africanene 1, 9-aristolene 2, the ubiquitous batyl alcohol 7, two 4 alpha-methylsteroids, 4 alpha-methylcholest-24(28)-en-3 beta-yl acetate 5 and 4 alpha, 23, 24-trimethylcholest-22-enc-3 beta-yl acetate 6 two polyhydroxy steroids, 3 beta, 7 beta, 19-trihydroxyergosta-5, 24 (28)-diene 11 and 24-methylenecholestane-3 beta, 5 alpha, 6 beta-triol 12 in addition to three monohydroxysteroids, 24-methylcholesta-7, 25-diene-3 beta-ol 8, 24-ethylidenecholest-5-en-3 beta-ol (Delta(5)-avenasterol, 9) and 24-ethylcholest-5-en-3 beta-ol 10. Besides the report of two new terpenoids, this is the first report on the presence of 4 alpha-methylsteroids in a Nephthea species.