Polyoxygenated steroids from the gorgonian Isis hippuris.

Eleven new hippuristanols (1-4, 7-9, and 11-14), along with eight known metabolites (5, 6, 10, and 15-19), have been isolated from the gorgonian coral Isis hippuris. Single-crystal X-ray diffraction analyses supported the structure elucidation of known steroids 5 and 10. The absolute structures of hippuristanols were established by application of modified Mosher's method on 19.

Hippuristerones E-I, new polyoxygenated steroids from the gorgonian coral Isis hippuris.

Five novel (22R,23S,24S)-steroids, hippuristerones E-I (1-5), have been isolated from the gorgonian coral Isis hippuris. The structures of steroids 1-5 were deduced by extensive 1D and 2D NMR studies ((1)H, (13)C, (1)H-(1)H COSY, HMQC, HMBC, and NOESY experiments). The structure of 1 was further supported by molecular mechanics calculations.