Mass spectrometry in structural and stereochemical problems. XXXVI. Alkaloids of periwinkles--27; the mass spectra of stereoisomers of the sarpagine-akuammidine group.
Explore the source record for details and available documents.
Alkaloids↗
Biomedical subjects
C Djerassi
Publications and source records attributed to C Djerassi.
Mass spectrometry in structural and stereochemical problems. XIX.. Akuammicine and related alkaloids.
Explore the source record for details and available documents.
Alkaloids↗
Synthesis of 5,9-hexacosadienoic acid phospholipids. 11. Phospholipid studies of marine organisms.
The synthesis of phosphatidylcholines (PC), phosphatidylethanolamines (PE) and phosphatidylserines (PS) containing two acyl chains of the naturally occurring sponge fatty acid (5Z,9Z)-5,9-hexacosadienoic acid as well as its hitherto unknown geometrical isomers is described. The PCs were prepared by deacylation of natural lecithins, followed by reacylation with fatty acid anhydrides. The synthesis of mixed-acid PCs is also reported: a diacyl product was converted to the lyso-PC by treatment with phospholipase A2 and subsequent acylation of the secondary hydroxyl group to give the desired mixed-acid PCs. The PEs and the PSs were prepared from the corresponding PCs by enzymatic transphosphatidylation catalyzed by phospholipase D. Structural assignments of the compounds were confirmed by spectroscopy (1H-NMR and MS). Ammonia chemical ionization mass spectrometry provided molecular ion and significant fragment peaks for PCs and PEs.
Animals↗
Mass spectral behavior and HPLC of some unusual molecular phospholipid species.
The molecular species of the major phospholipids from the marine sponges Parasperella psila and Microciona prolifera were studied using chemical hydrolysis, enzymatic degradation and capillary gas chromatography (GC), high performance liquid chromatography (HPLC), desorption chemical ionization (DCI), fast atom bombardment (FAB) combined with collisionally activated decomposition (CAD) mass spectrometry. Two new solvent systems were developed for the isolation of these species from the sponges. Our investigations indicated the existence of unusual symmetrical phospholipids as major components. 1,2-Di-(5Z,9Z)-5,9-hexacosadienoyl-sn-glycero-3-phosph oethanolamine was found in both organisms, while 1,2-di(5Z,9Z,19Z)-5,9,19-hexacosatrienoyl-sn-gly cero-3-phosphoethanolamine was present in M. prolifera, 1,2-Di-(4Z,7Z,10Z,13Z,16Z,19Z)-4,7,1 0,13,16,19-docosahexaenoyl-sn-glycero-3- phosphocholine was the major molecular species in the PC fraction of M. prolifera.
Animals↗
Minor and trace sterols in marine invertebrates 53 (1): Further novel marine sterols resulting from triple and quadruple biomethylation of the cholesterol side-chain.
The isolation and structure elucidation of nine new trace sterols with highly branched side chains from a Pseudaxinyssa species from the Australian Great Barrier Reef are described.
Animals↗
The crystal structure of 3 beta-hydroxy-4 alpha, 23R, 24R-trimethyl-5 alpha-cholestane (23R, 24R-5 alpha-dinostanol) from dinoflagellates.
An x-ray crystal structure determination of a dinostanol from the dinoflagellate Protoceratium reticulatum and zooxanthellae from Orbulina universa was completed. The novel sterol was shown to be 3 beta-hydroxy-4 alpha, 23R,24R-trimethyl-5 alpha-cholestane and may be one of the molecular fossils found in sediment cores from the deepest Black Sea trench.
Chemical Phenomena↗
Minor and trace sterols in marine invertebrates. 61. Isolation and structure elucidation of new A-nor sterols from the marine sponge Phakellia aruensis.
An examination of the Australian sponge Phakellia aruensis led to the isolation and identification of sterols with six different nuclei. Eight new sterols were isolated which included three delta 15-A-nor sterols, three delta 7-A-nor sterols, and two saturated A-nor sterols. Their structures were established through mass spectrometry and 1H-NMR spectral studies.
Animals↗
Minor and trace sterols in marine invertebrates. 62. Novel coprostanols with unusual side chains from the marine sponge Calyx nicaeensis.
Seventeen stanols with a variety of unusual side chains and possessing the rare 5 beta-dihydro nucleus have been isolated from the sponge Calyx nicaeensis. These stanols probably result from bacterial metabolism of the endogenous sponge sterols.
Animals↗
Biosynthetic studies of marine lipids 36. The origin of common sterol side chains in eleven sponges using [3-3H]-squalene.
1. [3-3H]-Squalene was fed to 11 marine sponges containing a mixture of "common" sterol side chains. All of these sponges possess significant quantities of cholesterol, but their ability to biosynthesize it differs widely. 2. All the sponges possess significant quantities of delta 22 sterols, yet none of them was able to introduce the delta 22 double bond. 22-Dehydro-24-norcholesterol and 24-methyl-22-dehydro-27-norcholesterol side chains also originate from the diet. 3. These sponges biosynthesized between 40 and 80% of their sterols, a typical value being 70%. The remainder is derived from the diet or by modification of dietary sterols.
Animals↗
What contraceptive revolution?
Explore the source record for details and available documents.
Contraception↗
The revolution revisited.
Explore the source record for details and available documents.
Contraceptive Agents, Female↗