Minor and trace sterols in marine invertebrates. Part 20. 3ξ-Hydroxymethyl-A-nor-patinosterol and 3ξ-hydroxymethyl-A-nor-dinosterol. Two new sterols with modified nucleus and side-chain from the sponge Teichaxinella morchella

Abstract

The sponge Teichaxinella morchella from the Gulf of Mexico has been shown to contain solely 3ξ-hydroxymethyl-A-nor-sterols, of which two are the new 3ξ-hydroxymethyl-A-nor-patinosterol and 3ξ-hydroxmethyl-A-nor-dinosterol, isolated as acetates (1) and (12), respectively. The 24R and 24S epimers of both 24-methyl-[(4) and (5)] and 24-ethyl-[(8) and (9)] 3ξ-acetoxymethyl-A-nor-5α-cholest-22-ene were separated by reverse-phase HPLC while the corresponding saturated compounds were isolated as epimeric pairs. The 360-MHz n.m.r. spectra of the 3-acetoxymethyl-A-nor-sterols are discussed. The sole occurrence of A-nor-sterols and the absence of conventional sterols suggest that they are all bio-transformation products of dietary precursors. Attention is called to the potential chemo-taxonomic significance of this observation.