The steroidal components of a Red Sea sponge, Biemna fortis, were fractionated through reversed phase HPLC. and analyzed by a combination of physical methods, including high resolution GC./MS. and 360 MHz 'H-NMR. The sponge contains five conventional d5-sterols, la-c, le, l g , which comprise about 25% of the mixture and 2,5% of gorgosterol (lh), a sterol never found before in Porifera. Three ~l~~~~~~-s t e r o l s were also present as major components in the mixture ( N 70%): cholesta-5,7,22-trien-3,f?-ol (Za), ergosta-5,7,22-trien-3/?-01 (2c) and (24R)-ethylcholesta-5,7,22-trien-3~-oI (2e) whereas two new tetra-unsaturated sterols were identified in minor amounts (2%): ergosta-5,7,9 (1 l), 22-tetraen-3P-01 (3c) and 24(-ethylcholesta-5,7,9 (1 l), 22-tetraen-3P-01 (3e or 3f). NMR. spectroscopy made possible the assignment of a 24R configuration for all the C(24) substituted sterols isolated in sufficient amount from the mixture. The possible symbiotic, dietary or biosynthetic origins of these sterols are discussed.Introduction. -Marine organisms such as sponges constitute a rich source of sterols possessing unusual side-chains or unconventional ring systems [2-61. Besides their chemical structure elucidation such sterols raise interesting questions in terms of biosynthesis and biological function [7]. Against this background and in our continuing search for key biosynthetic intermediates among the minor and trace components of marine sterol mixtures [ 11, we report the composition of the Red Sea sponge Biemna fortis.Results. -The gas-liquid chromatographic (GC.) and combined gas chromatographic-mass spectrometric (GCJMS.) analyses of the free sterol mixture allow the resolution of the number, the identity, and the amount of the components. These data are corroborated by the GC./MS. analysis on capillary columns of the trimethylsilyl ethers of the mixture. Further separations of the free sterols by high I) Part XIV in the Stanford series 'Minor and Trace Sterols in Marine Invertebrates'. Part XIII: [l].

Identification of short side chain sterols in the sponge Damiriana hawaiiana SummaryThe steroidal composition of the sponge Damiriana hawaiiana is examined. Twenty-seven components are identified. In addition to the (&-CZ9, A*-mono and diunsaturated sterols, the sponge contains sterols without side-chain: androsta-5,16-dien-3/3-01 (l), androst-5-en-3P-o1(2); sterols with a non-functionalized sidechain consisting of two, three, four, five and six carbon atoms: pregna-5,20-dien-38-01 (5), pregn-5-en-3P-o1(6), 23,24-bisnor-chola-5,20-dien-3,B-ol(7), 23,24-bisnorcho1-5-en-3P-o1(8), 24-nor-chol-5-en-38-01 (lo), chol-5-en-3P-01 (ll), 26,27-bisnorcholest-5-en-3j?-ol(12), and sterols possessing a short oxygenated side-chain such as 3~-hydroxy-androst-5-en-l7-one (3), androst-5-en-38,17j?-diol(4) and 3,B-hydroxy-26,27-bisnor-22-trans-cholesta-5,22-dien-24-one (14). The probable biological or dietary origin rather than artifact production of these hitherto undescribed components from marine sources is supported by their relatively high concentration and their relative proportions, both very different from those expected for autoxidation.

SummaryThe I3C-and '70-chemical shifts of 31 aliphatic ethers are measured and discussed. The 170-chemical shifts of the ethers ROR' correlate with chemical shifts for the methylene groups of the corresponding alkanes RCH2R'. The constant of proportionality can be related to the orbital expansion term (r-3)2p. The 6, for carbon atoms can also be correlated with 6, for the corresponding alkanes. The origin of the correlation is discussed taking into account the conformational modifications resulting from introduction of an oxygen atom in an alkyl chain.

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