52689-37-9Relevant academic research and scientific papers
(20R,23E)-eupha-8,23-diene-3β,25-diol from Tripetalum cymosum
Leong, Yuan-Wah,Harrison, Leslie J.
, p. 849 - 857 (1999)
A new euphane triterpenoid, (20R,23E)-eupha-8,23-diene-3β,25-diol, was isolated from the leaves of Tripetalum cymosum and its structure was determined by spectral analysis and chemical correlation with euphol. Caryophyllene oxide, friedelin, euphol and putranjivic acid were also obtained from the leaves whilst the bark afforded euphol, glutin-5-en-3β- ol, butyrospermol and dammara-20,24-dien-3β-ol.
Oxyfunctionalization of unactivated C-H bonds in triterpenoids with tert-butylhydroperoxide catalyzed by meso-5,10,15,20-tetramesitylporphyrinate osmium(II) carbonyl complex
Ogawa, Shoujiro,Wakatsuki, Yasuo,Makino, Mitsuko,Fujimoto, Yasuo,Yasukawa, Ken,Kikuchi, Takashi,Ukiya, Motohiko,Akihisa, Toshihiro,Iida, Takashi
experimental part, p. 165 - 171 (2010/06/19)
A system consisting of meso-5,10,15,20-tetramesitylporphyrinate osmium(II) carbonyl complex [Os(TMP)CO] as a precatalyst and tert-butylhydroperoxide (TBHP) as an oxygen donor is shown to be an efficient, regioselective oxidant system for the allylic oxidation, ketonization and hydroxylation of unactivated C-H bonds in a series of the peracetate derivatives of penta- and tetracyclic triterpenoids. Treatment of the substrates with this oxidant system afforded a variety of novel or scarce oxygenated derivatives in one-step. Structures of the isolated components, after chromatographic separation, were determined by spectroscopic methods including GC-MS and shift-correlated 2D-NMR techniques. Factors governing the regioselectivity and the possible mechanism for the oxyfunctionalization of the unactivated carbons are also discussed.
1H and 13C NMR Assignments for Lanostan-3β-ol Derivatives: Revised Assignments for Lanosterol
Emmons, Gary T.,Wilson, William K.,Schroepfer, George J. Jr
, p. 1012 - 1024 (2007/10/02)
1H and 13C NMR assignments are presented for 30 oxygenated lanostane derivatives, including lanosterol, dihydrolanosterol, 7-ketolanosterol, agnosterol, 24,25-epoxylanosterol, 8α,9α-epoxylanostan-3β-ol, three 15-oxygenated derivatives of lanost-7-en-3β-ol, lanostane-3β,7α-diol, lanostane-3B,9α-diol and their acetates.These assignments, which were largely determined by a combination of DEPT, one-bond and long-range 13C-1H chemical shift correlation and lanthanide-induced shift experiments, are not dependent on previously reported assignments, several of which were found to be incorrect. 1H and 13C acetylation shifts for lanostan-3β-ols were sufficiently invariant among the sterols studied that they were useful for assigning carbons in rings A and B.The acetylation shifts reported for lanostan-3β-ols were extended and partially revised.-- Key Words 1H and 13C NMR Oxygenated lanostane derivatives Spectral assignment Lanthanide-induced shifts Long-range HECTOR Acetylation shifts
Triterpenes issus des latex des euphorbes cactoides marocaines E. resinifera, E. echinus et E. officinarum : isolement, etude comparative par RMN (13)C des quatre classes tetracycliques, eupho-lanostane, elemo-lanostane, lanostane, et nor-31 lanostane
Harref, A. Ben,Lavergne, J.-P.
, p. 965 - 972 (2007/10/02)
The latex of moroccan Euphorbia : E. resinifera, E. echinus et E. officinarum has been examined for triterpene content.Three tetracyclic triterpenes from E. resinifera and ten penta or tetracyclic triterpenes including 4α-methyl sterols from E. echinus and E. officinarum, have been isolated.The carbon-13 NMR spectra have been recorded and all carbon shifts have been assigned for representatives of the four classes of tetracyclic triterpenes.It has been found that the differences in the 3-C, 9-C, 17-C, 20-C and 21-C chemical shifts for these triterpenes are remarkable, being significant for the characterization of the four classes.
Terpenoids and Phenolics from Cassia tora Stem Bark
Chakrabarty, Kakoli,Chawla, Mahindra H.
, p. 1165 - 1166 (2007/10/02)
The first natural occurance of 3,5,8,3',4',5'-hexahydroxyflavone and a hydroxycoumarin, aurapterol from Cassia tora stem bark is reported.Euphol, basseol, emodin, rhein, palmitic acid, isostearic acid, behenic acid, ethyl arachidate and β-sitosterol have also been isolated from this source the first time.
