1259-10-5Relevant academic research and scientific papers
3-EPI-CYCLOLAUDENOL AND KNOWN TRITERPENES FROM EUPHORBIA CAUDICIFOLIA
Govardhan, Ch.,Prasad Reddy, R.,Sundararamaiah, T.
, p. 411 - 414 (1984)
A new tetracyclic triterpene, 3-epi-cyclolaudenol (24-methyl-9,19-cyclolanost-25-en-3α-ol), cyclolaudenol and cycloartenol were isolated from the ethanolic extract of the latex of Euphorbia caudicifolia, and cycloartenol and 3-ketomethylursolate were obtained from the ethanolic extract of the stem of this plant. - Keywords: Euphorbia caudicifolia; Euphorbiaceae; latex; stem; tetracyclic triterpenes; pentacyclic triterpenes; 3-epi-cyclolaudenol; cyclolaudenol; cycloartenol; 3-ketomethylursolate.
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.
Conformational Analysis of Cycloartenol, 24-Methylenecycloartanol and Their Derivatives
Yoshida, Kumi,Hirose, Yoshihiko,Imai, Yutaka,Kondo, Tadao
, p. 1901 - 1912 (2007/10/02)
A conformational analysis of cycloartenol, 24-methylenecycloartenol and their derivatives was carried out in the solution and the solid state by an NMR study and X-ray crystallographic analysis, respectively.Complete assignments of the 1H NMR spectra of these compounds were made in order to elucidate the conformation involving the ring system and side chain.Rings A to C had a chair-halfchair-boat conformation, and the side chain had a zig-zag conformation.
BIOSYNTHESIS OF SITOSTEROL, CYCLOARTENOL, AND 24-METHYLENECYCLOARTANOL IN TISSUE CULTURES OF HIGHER PLANTS AND ERGOSTEROL IN YEAST FROM -AND 2H3>-ACETATE AND 2H2>MVA
Seo, Shujiro,Uomori, Atsuko,Yoshimura, Yohko,Takeda, Ken'ichi,Seto, Haruo,et.al.
, p. 2407 - 2414 (2007/10/02)
The -methyl migrations postulated in the 'biogenetic isoprene rule' proposed by Ruzicka et al. have been verified by (13)C n.m.r. spectroscopy in the biosynthesis of cycloartenol (10a), 24-methylenecycloartenol (11a), and sitosterol (12a) using cultured cells of higher plants, Rabdosia japonica and Physalis peruviana, and of ergosterol (14a) in yeast fed with acetate.The -hydride shifts from C-17 to C-20, and C-13 to C-17 have also been demonstrated in the biosynthesis of sitosterol (12b) in R. japonica and of ergosterol (14b) in yeast fed with acetate.THe -hydride shift from C-9 to C-8 has also been verified in 24-methylenecycloartanol (11b) fed acetate to tissue cultures of Trichosanthes kirilowii Maxim. var. japonica.In the side-chain formation of 24-methylenecycloartanol (11b) and ergosterol (14b), a -hydride (deuteride) shift from C-24 to C-25 is observed.Conversely, no deuterium atom at C-24 or C-25 is observed in sitosterol (12b) formation.Both C-11 and C-12 of sitosterol (12c) labelled as(13)C-(2)H2 and (13)C-(2)H(1)H, biosynthesized from MVA in R. japonica suggest that squalene is released from an enzyme and the following oxidation does not distinguish a terminal double bond of one farnesyl moiety from the other to form epoxysqualenes (8A) and (8B).
