An efficient epoxidation process for various terpenes and styrenes using a hydrogen peroxide-tungsten catalytic system with organic solvent- and halide-free conditions was developed. In the presence of the catalytic system, Na2WO4, PhP(O)(OH)2, and [Me(n-C8H17)3N]HSO4, and under weak acidic conditions, hydrogen peroxide successfully epoxidized α-pinene to α-pinene oxide in 95% selectivity at 91% conversion
开发了一种在无有机溶剂和无卤化物条件下使用过氧化氢-钨催化体系对各种萜烯和苯乙烯进行高效环氧化的方法。在催化体系Na 2 WO 4,PhP(O)(OH)2和[Me(n -C 8 H 17)3 N] HSO 4的存在下,在弱酸性条件下,过氧化氢成功地环氧化了α -pine烯至α-pine烯氧化物的转化率为95%,转化率为91%,而先前公布的利用NH 2 CH 2 P(O)(OH)2作为促进剂的条件没有提供环氧化物。 氧化-催化-环氧化物-萜类化合物-苯乙烯
An effective procedure for the synthesis of acid-sensitive epoxides: Use of 1-methylimidazole as the additive on methyltrioxorhenium-catalyzed epoxidation of alkenes with hydrogen peroxide
作者:Shigekazu Yamazaki
DOI:10.1039/b926575a
日期:——
An effective method for suppression of ring opening and rearrangement of acid-sensitive epoxides during methyltrioxorhenium(MTO)-catalyzed epoxidation of alkenes with H2O2 by using 1-methylimidazole as a co-additive has been found. The combined use of 3-methylpyrazole and 1-methylimidazole as the additives has been found to be an effective procedure that affords excellent yields of acid-sensitive epoxides for MTO-catalyzed epoxidation.
A further step to sustainable palladium catalyzed oxidation: Allylic oxidation of alkenes in green solvents
作者:Maíra dos Santos Costa、Amanda de Camargo Faria、Rayssa L.V. Mota、Elena V. Gusevskaya
DOI:10.1016/j.apcata.2021.118349
日期:2021.9
The palladiumcatalyzedoxidation of alkenes with molecular oxygen is a synthetically important reaction which employs palladium catalysts in solution; therefore, a solvent plays a critical role for the process. In this study, we have tested several green solvents as a reaction medium for the allylic oxidation of a series of alkenes. Dimethylcarbonate, methyl isobutyl ketone, and propylene carbonate
Neuronal growth promoting sesquiterpene–neolignans; syntheses and biological studies
作者:Xu Cheng、Nicole Harzdorf、Zin Khaing、Danby Kang、Andrew M. Camelio、Travis Shaw、Christine E. Schmidt、Dionicio Siegel
DOI:10.1039/c1ob06363d
日期:——
The use of small molecules that can promote neuronal growth represents a promising approach to regenerative science. Along these lines we have developed separate short or modular syntheses of the natural products caryolanemagnolol and clovanemagnolol, small molecules previously shown to promote neuronal growth and induce choline acetyltransferase activity. The postulated biosynthetic pathways, potentially leading to the assembly of these molecules in nature, have guided the laboratory syntheses, allowing the preparation of both natural products in as few as two steps. With synthetic access to the compounds as single enantiomers we have examined clovanemagnolol's ability to promote the growth of embryonic hippocampal and cortical neurons. Clovanemagnolol has been shown to be a potent neurotrophic agent, promoting neuronal growth at concentrations of 10 nM.
A catalyticsystem that operates well for the epoxidation of α-pinene,a very challenging substrate, at near-neutral pH and ambient temperaturewithout organic solvent was developed. With hydrogenperoxide asa terminal oxidant, combination of Na 2 WO 4 , PhP(O)(OH) 2 ,and [Me( N-C 8 H 17 ) 3 N]HSO 4 successfullycatalyzed the epoxidation of α-pinene to give α-pineneoxide in 95% selectivity at 91% conversion