Tamosterone Sulfates: A C-14 Epimeric Pair of Polyhydroxylated Sterols from a New Oceanapiid Sponge Genus.

Two novel, C-14 epimeric polyhydroxylated 15-keto steroid sulfates, tamosterone sulfate and 14beta-tamosterone sulfate (1 and 2), were isolated from a sponge belonging to a new genus collected in Yap, Federated States of Micronesia. Their structures were assigned by analysis of spectroscopic data and chemical conversions. 14beta-Tamosterone sulfate (2) has the rare naturally occurring C/D cis ring fusion and is the less stable epimer based on equilibration studies. Both compounds possess side-chain substitution patterns not observed previously in marine sterols.