1,721,075 research outputs found
New dihydroxylated sterols from the marine sponge Spongionella gracilis
No full textThree new dihydroxylated sterols were isolated from the marine sponge S. gracilis by extn. with Me2CO and Et2CO followed by chromatog. on silica gel and HPLC. The structures of these substances were determined by spectral analyses and chemical conversion to the corresponding acetates
FOUR NEW TRIHYDROXYLATED STEROLS FROM THE SPONGE SPONGIONELLA-GRACILIS
No full textEight 3β,5α,6β-trihydroxysterols were isolated from the sponge S. gracilis, of which 4 are new. The structures of the new compds. were elucidated by IR, 1H and 13C NMR, high-resoln. mass spectroscopy and chemical evidenc
A NEW C-30 STEROL, (24Z)-24-PROPYLCHOLESTA-5,7,24(28)-TRIEN-3-BETA-OL, AND OTHER DELTA-5,7 STEROLS FROM THE SPONGE SPONGIONELLA-GRACILIS
No full textThe sterol mixt. of the marine sponge S. gracilis (Dictyoceratida:Dysideidae) was fractionated by reverse-phase HPLC and argentic TLC and analyzed by spectroscopic methods. The sponge contain mainly Δ5,7-sterols (92%) accompanied by Δ5-sterols. The Δ5,7-sterols were isolated and characterized by UV, 1H-NMR, and mass spectroscopy. Ergosterol and 24-ethylcholesta-5,7-dien-3β-ol were the major components of the sterol mixt. A new C30 sterol was detected as a minor component and characterized as (24Z)-24-propylcholesta-5,7,24(28)-trien-3β-ol (I). A rare marine sterol, identified as 24-methylcholesta-5,7,24(28)-trien-3β-ol, was also present
MINOR BISNORDITERPENES FROM THE MARINE SPONGE SPONGIONELLA-GRACILIS AND REVISION OF THE DELTA-6 CONFIGURATION OF GRACILIN-B
No full textTwo new representatives of the rare class of bisnorditerpenes, gracilin C (I) and D II were isolated as minor metabolites from S. gracilis, a Mediterranean sponge. The structure of these compds., both related to that of gracilin B (III), the major metabolite of S. gracilis, were solved by spectral analyses, including 2-dimensional NMR spectroscopy, and chem. interconversions. The structure of III was revised on the basis of addnl. NOE difference expts. and 13C NMR data
Nitrogenous sesquiterpenes from the marine sponge Acanthella acuta. Three new isocyanide-isothiocyanate pairs
No full textThe isolation and the structure elucidation of 6 new nitrogenous sesquiterpenes (I-VI) from the marine sponge A. acuta are described. A complete 1H- and 13C-NMR assignment for the new metabolites, which form 3 new isocyanide-isothiocyanate pairs, was accomplished with the aid of carbon-proton shift-correlated, two-dimensional NMR expts
Spongiolactone, an unusual ƒÒ-lactone diterpene isovalerate based on a new rearranged spongiane skeleton from Spongionella gracilis
No full textSpongiolactone, an unusual ƒÒ-lactone diterpene isovalerate based on a new rearranged spongiane skeleton from Spongionella gracilis
No full textFrom a further investigation of the extractives of the mediterranean sponge S. gracilis a new diterpene isovalerate, spongiolactone, was isolated and its stereostructure elucidated on the basis of chem. and physicochem. evidenc
Application of 2D-NMR spectroscopy in the structural determination of gracilin B, a bis-nor-diterpene from the sponge Spongionella gracilis
No full textThe structure of gracilin B (I), an unusual metabolite based on a bisnorditerpene skeleton isolated from S. gracilis, was detd. mainly by using two-dimensional heteronuclear 13C-1H shift correlation spectroscopies
Δ5,7Sterols from the sponges Ircinia pipetta and Dysidea avara. Identification of cholesta-5,7,24-trien-3β-ol
No full textΔ5,7-Sterols were isolated as pure compds. from the marine sponges I. pipetta (Dictyoceratida:Thorectidae) and D. avara (Dictyoceratida:Dysideidae) by reversed-phase HPLC and analyzed by gas-liq. chromatog., U.V., mass spectrometry, and 1H-NMR. I. pipetta And D. avara had rather similar sterol compns. and contained predominantly Δ5,7-sterols, accompanied by α5-sterols. Ergosterol, cholesta-5,7-dien-3β-ol, and 24-ethylcholesta-5,7-dien-3β-ol were the major sterols in I. pipetta, whereas D. avara contained in addn. to these 3 sterols, (24X)-24-ethylcholesta-5,7,24(28)-trien-3β-ol as the 4th major sterol. Cholesta-5,7,24-trien-3β-ol which previously was not isolated from a marine organism is also presen
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