Preparative Method for the Quantitative Separation of Methylenic Sterols from Unsaturated Sterol Mixtures by Chemoselective Hydroxymercuration-Deoxymercuration
作者:Laïla El Kihel、Georges Charles
DOI:10.1055/s-2006-942495
日期:2006.8
intermediates were easily purified by flash chromatography on silica gel column and the reactive alkenes were regenerated by deoxymercuration in a biphasic system (ethyl acetate/I M HCl, 2:1 ratio). These conditions leave the ring double bonds of steroids intact. No isomerization of methylene double bonds was observed.
Investigations on the Δ23-, Δ24(28)- and Δ25-Sterols of zea mays
作者:Neil L.A. Misso、L. John Goad
DOI:10.1016/0031-9422(84)83081-2
日期:1984.1
25 -compound, cyclolaudenol, were recognized. These various Δ 23 - and Δ 25 -sterols may have some importance in alternative biosynthetic routes to the major sterols, particularly the 24β-methylcholest-5-en-3β-ol component of the C 28 -sterols. Radioactivity from both [2- 14 C]MVA and [methyl- 14 C]methionine was incorporated by Z. mays shoots into the sterol mixture. Although 24-methylene and 24-ethylidene
Untersuchungen uber Steroide. XXXI. Umlagerung einer Doppelbindung an C<SUB>24 (28)</SUB> der Sterin-Seitenkette bei Einwirkung von Jod.
作者:Kiyoshi Sakai
DOI:10.1248/cpb.11.752
日期:——
Es wird eine Umlagerungsreaktion der Doppelbindung an C24 (28) der Sterinseitenkette beschrieben. Die Doppelbindung an C24 (28) des Fucosterylacetates bzw. des 24-Methylencholesterylacetates laβt sich durch Einwirkung von Jod in die 24 (25)-Stellung umlagern.
Ergosta-5,23-dien-3β-ol and ergosta-7,23-dien-3β-ol, two new sterols from Zea mays etiolated coleoptiles
作者:Francoise Scheid、Pierre Benveniste
DOI:10.1016/0031-9422(79)80136-3
日期:1979.1
Abstract Ergosta-5,23-dien-3β-ol and ergosta-7,23-dien-3β-ol were identified for the first time in maize etiolatedcoleoptiles. They represent more than 11 % of the total 4-desmethyl sterol fraction. It is suggested that they could play some role in the biosynthesis of 24-methyl sterols of this material.
24-Methyl-23-dehydrocholesterol: A new sterol intermediate in C-24 demethylation from the nematodes Panagrellus redivivus and Caenorhabditis elegans?
作者:Thomas A. Salt、Ruben Lozano、William R. Lusby、David J. Chitwood、Malcolm J. Thompson
DOI:10.1016/0039-128x(86)90031-0
日期:1986.11
Panagrellus redivivus produced 24-methyl-23-dehydrocholesterol as 4.0% of the 4-desmethylsterols when propagated in a medium containing campesterol as the dietary sterol. The re-examination of previous data revealed that Caenorhabditis elegans produced 1.8% 24-methyl-23-dehydrocholesterol when propagated in medium containing campesterol. 24-Methyl-23-dehydrocholesterol was not detected when the nematodes were propagated in medium containing 22-dihydrobrassicasterol or 24-methylenecholesterol. This may be a result of the greater efficiency of dealkylation of the latter two sterols. This is the first report of the natural occurrence of this sterol in a non-photosynthetic organism, and the first report in organisms that dealkylate 24-alkylsterols.