Search results for "Lactone"
showing 10 items of 335 documents
Addition of reducing agent dithiothreitol improves 4-decanolide synthesis by the genus Sporidiobolus.
2000
Two species of the genus Sporidiobolus, S. johnsonii and S. ruinenii, were used to study the effect of the reducing agent, dithiothreitol (DTT), on 4-decanolide production using ricinoleic acid as the substrate. The results indicate that the addition of DTT into the cultures significantly enhanced 4-decanolide biosynthesis by the two species.
Sesquiterpene lactones from Anthemis plutonia.
1998
Abstract Aerial parts of Anthemis plutonia furnished three guaianolides, one of them new.
Acetogenins from Annona glabra seeds
1998
Abstract From the cytotoxic ethanol extract of Annona glabra seeds, a new mono-tetrahydrofuranic (mono-THF) acetogenin, glabranin, as well as pair of 22-epimer bis-THF acetogenins, were isolated by semipreparative HPLC. Four known mono-THF acetogenins with an identical threo/trans/threo relative configuration, annonacin, annonacinone, corossolin and corossolone, were found to be potent inhibitors of complex I of the mitochondrial respiratory chain.
New sesquiterpene lactones and acetylenes from chrysanthemum lavandulifolium
1990
Abstract The aerial parts of Chrysanthemum lavandulifolium Mak. (Asteraceae) yielded three new acetylenes of the spiroacetal type 1-3, as well as two new germacranolides 4-5 and several known lactones.
Rollimembrin, a novel acetogenin inhibitor of mammalian mitochondrial complex I
1997
Abstract Rollimembrin (3), is a new adjacent bis-tetrahydrofuranic acetogenin with a scarce relative configuration, threo/cis/threo/cis/erythro, isolated from Rollinia membranacea seeds. The mechanism of cytotoxic activity, determined by NADH-oxidase experiments, establish that rollimembrin (3) is the most potent inhibitor of mammalian mitochondrial complex I.
Synthetic studies on neoclerodane diterpenes from Salvia splendens: oxidative modifications of ring A.
2011
Salvinorin A (1), a neoclerodane diterpene from the hallucinogenic mint Salvia divinorum, is the only known naturally occurring non-nitrogenous and specific κ-opioid agonist. Some oxidative modifications of the A ring in the congeners of 1 isolated from Salvia splendens salviarin, splenolide B, splendidin and in the non-natural 8-epi-salviarin gave new derivatives, some of which were tested as agonists at opioid receptors. However, none of these compounds were active. The presence of the C-18, C-19 lactone could be at the origin of the observed lack of binding affinity.
Oxygenated germacranes from Santolina chamaecyparissus
1993
The polar fraction of an extract of Santolina chamaecyparissus ssp. squarrosa yielded six new germacrane derivatives and a novel seco-germacrane lactone. The structures have been derived from spectral data, X-ray diffraction and chemical correlations.
Production of 6-pentyl-?-pyrone byTrichoderma harzianum from 18?n fatty acid methyl esters
1992
Biosynthesis of 6-pentyl-α-pyrone byTrichoderma harzianum in two different media was evaluated. Best yields were found in nitrogen deficient medium (C/N=60). Limited growth seems to favour the production of this lactone. When fungal cells, precultured in low nitrogen medium, were incubated on methyl ricinoleate (10 g/l, C/N=60) an increase in 6-pentyl-α-pyrone production was observed in comparison with the media containing methyl oleate or methyl linoleate.
(-)-(5S,8S,9R,10S,13R,14R)-15,16-Dideoxy-16,17-epoxy-16-oxospongian-15-yl acetate.
2006
The title compound (aplyroseol-14), C22H34O4, exhibits a lactone-based structure that is novel for spongian-type diterpenoids. The structure, which features a six-membered lactone ring, was proposed by Arno, Gonzalez & Zaragoza [J. Org. Chem. (2003), 68, 1242–1251] on the basis of spectroscopic data and chemical correlations. This assignment has been confirmed, and it is shown that the molecule contains a trans–anti–trans 6/6/6 tricyclic hydrocarbon system and that the acetoxymethyl group lies in an equatorial position. Pairs of near-linear C—H⋯O interactions link molecules into extended chains.
Preparation of 4-substituted 1,3-oxathiolan-5-onesviathe sulphenium ion intermediate generated by the pummerer rearrangement
1993
4-Substituted 1,3-oxathiolan-5-ones have been synthesized via the Pummerer rearrangement from the S-oxide of the parent molecule. The 4,5-dione is obtained in the presence of pyridine N-oxide.