61203-71-2Relevant articles and documents
Biosynthesis of Triterpenes, Ursolic Acid, and Oleanolic Acid in Tissue Cultures of Rabdosia japonica Hara Fed Mevalonolactone and Acetate
Seo, Shujiro,Yoshimura, Yohko,Uomori, Atsuko,Takeda, Ken'ichi,Seto, Haruo,et al.
, p. 1740 - 1745 (1988)
Mevalonolactone and sodium acetate were fed to suspension cultures of Rabdosia japonica Hara.The (13)C-(2)H labeling patterns analysed by (13)C-NMR spectroscopy for methyl ursolate (13) and methyl oleanolate (15) give the biosynthetic information for all the hydrogen atoms composing mevalonic acid incorporated into these two triterpenes.The combination of the labeling patterns on C(11)-C(12) in one molecule of ursolate from MVA being (13)C(11)(2)H2-(13)C(12)(2)H and (13)C(11)(2)H(1)H-(13)C(12)(2)H differ from those of oleanolate .This indicates that ursolic acid (12) and oleanolic acid (14) are formed from both oxidosqualenes 8 and 9 and the 12(13) double bond of 12 is formed by elimination of the 12-pro-R hydrogen atom of 10 and 11 in a cis mode.Three signals shifted by β-deuterium atoms verify the 1,2-hydride shifts (20-H from C-19,19-H from C-18, and 18-H from C-13) in the biosynthesis of ursolic acid (12) from acetate.Two β-deuterium-shifted signals confirm the 1,2-hydride shifts (19-H from C-18 and 18-H from C-13) in the biosynthesis of oleanolic acid (14) from acetate.
Simple and efficient preparation of [10,20-13C2]- and [10-CH3,13-13C2]-10-methylretinal: Introduction of substituents at the 2-position of 2,3-unsaturated nitriles
Verdegem,Monnee,Lugtenburg
, p. 1269 - 1282 (2007/10/03)
In this paper, we present the synthesis of [10,20-13C2]-10-methylretinal and [10-CH3,13-13C2]-10-methylretinal, two doubly 13C-labeled chemically modified retinals that have been recently used to study the structural and functional details behind the photocascade of bovine rhodopsin (Verdegem et al. Biochemistry 1999, 38, 11316; de Lange et al. Biochemistry 1998, 37, 1411). To obtain both doubly 13C-labeled compounds, we developed a novel synthetic method to directly and regiospecifically introduce a methyl substituent on the 2-position of 3-methyl-5-(2′,6′,6′-trimethyl-1′ -cyclohexen-1′-yl)-2,4-pentadienenitrile. Encouraged by these results, we investigated the scope of this novel reaction by developing a general method for the introduction of a variety of substituents to the 2-position of 3-methyl-2,3-unsaturated nitriles, paving the way for simple and efficient synthesis of a wide variety of 10-, 14-, and 10,14-substituted chemically modified retinals, and other biologically important compounds.
THE CONVERSION OF 2-(METHYLTHIO)ETHANOL INTO 1-CHLORO-2-(METHYLTHIO)-ETHANE: A 13C-LABELLING STUDY WITH THE AID OF 13C NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY
Billington, David C.,Golding, Bernard T.
, p. 341 - 348 (2007/10/02)
The synthesis of 2-(methylthio)ethanol from acetic acid is described.This labelled alcohol and 13C NMR spectrocopy were used to evaluate the propensity for rearrangement of four methods for effecting the conversion ROH RCl.In every case the product observed at all stages of the reaction was a 1:1 mixture of 1-chloro-2-(methylthio)ethane and 1-chloro-2-(methylthio)ethane.It is proposed that activation of the hydroxy-group of 2-(methylthio)ethanol is followed by internal displacement by the methylthio-group giving the 1-methylthiiranium ion, which is captured by chloride.
