2 NEW LOBANE DERIVATIVES FROM THE SOFT CORAL LOBOPHYTUM-PAUCIFLORUM OF THE HAVELOCK-ISLAND OF THE INDIAN-OCEAN

A detailed chemical examination of the ethyl acetate extract of the so ft coral Lobophytum pauciflorum collected from the Havelock Island of the Indian Ocean furnishes two new lobane derivatives: a nor lobape al dehyde, lobophytal(1) and fuscolmethylether (2) along with nine known derivatives, two sesquiterpenes: Delta(9(15))-africanene (3) and 15-no r-13-keto-beta-elemene (4), three lobane diterpenes: 17, 18-epoxyloba- 8, 10, 13(15)-trien-16-ol (5), loba-8, 10, 13(15)-trien-16, 17, 18-tri ol-16, 17, 18-triacetate (6) and loba-8, 10, 13(15)-trien-16, 17, 18-t riol-16, 17-diacetate (7), and four steroids: (24S)-24-methylcholest-5 -en-3 beta, 25-diol (8), (24S)-24-methylcholestane-3 beta, 5 alpha, 6 beta, 25-tetrol-25-monoacetate (9), (24S)-24-methylcholestane-3 beta, 5 alpha, 6 beta, 25-tetrol(10) and (24S)-24-methylcholestane-1 beta, 3 beta, 5 alpha, 6 beta, 25-tetrol(11). The structures of the new loban e derivatives have been established as 17, 18, 19, 20-tetranorloba-8, 10, 13(15)E-trien-16-al (1) and (13E, 16E)-18-methoxyloba-8, 10, 13(15 ), 16-tetraene (2) by a study of their spectral [UV, IR, H-1 and C-13 NMR, DEFT, 2D NMR (H-1-H-1 COSY) and mass] data.