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61.
Lucia Z. Flores-López Miguel Parra-Hake Ratnasamy Somanathan Fernando Ortega Gerardo Aguirre 《合成通讯》2013,43(1):147-155
Synthesis of new chiral sulfonamide ligands derived from isatoic anhydride by reaction with trans-(R,R)-1,2-diaminocyclohexane and chiral aminoacid esters. 相似文献
62.
Trimethylsilylation of alcohols was achieved using 1,1,1,3,3,3-hexamethyldisilazane(HMDS) as silylating agent,in the presence of polyvinylpolypyrrolidonium tribromide in acetonitrile at room temperature.Also a variety of alcohols were converted into alkyl formates by ethyl formate and a catalytic amount of polyvinylpolypyrrolidonium tribromide under solvent free conditions at room temperature. 相似文献
63.
Poly(4-vinylpyridinium tribromide) was prepared from poly(4-vinylpyridin) and used for the selective oxidation of a variety of sulfides to the corresponding sulfoxides.The oxidation reaction was carried out heterogeneously in acetone/water,as green solvent, at room temperature. 相似文献
64.
The synthesis of dihydrochromeno[4,3-b]pyrazolo[4,3-e]pyridin-6(7H)-ones was achieved through one-pot three-component reaction from 4-hydroxycoumarin, aldehydes, and 3-amino-5-methyl-pyrazole in acetonitrile using 5 mol % TBATB as the catalyst under reflux condition. The product formation is through tandem Knoevenagel–Michael reaction followed by concomitant cyclization. Simple reaction procedure, shorter reaction time, good yields, avoidance of aqueous work-up, and column chromatographic separation are some of the salient features of the present protocol. 相似文献
65.
The kinetics of oxidation of five vicinal and four non-vicinal diols, and two of their monoethers by benzyltrimethylammonium
tribromide (BTMAB) have been studied in 3:7 (v/v) acetic acid-water mixture. The vicinal diols yield the carbonyl compounds
arising out of the glycol bond fission while the other diols give the hydroxycarbonyl compounds. The reaction is first-order
with respect to BTMAB. Michaelis-Menten type kinetics is observed with respect to diol. Addition of benzyltrimethylammonium
chloride does not affect the rate. Tribromide ion is postulated to be the reactive oxidizing species. Oxidation of [1,1,2,2-2H4] ethanediol shows the absence of a kinetic isotope effect. The reaction exhibits substantial solvent isotope effect. A mechanism
involving a glycol-bond fission has been proposed for the oxidation of the vicinal diols. The other diols are oxidized by
a hydride ion transfer to the oxidant, as are the monohydric alcohols. 相似文献
66.
Raghvendra Shukla Pradeep K. Sharma Kalyan K. Banerji 《Journal of Chemical Sciences》2004,116(2):101-106
The oxidation of eleven amino acids by tetrabutylammonium tribromide (TBATB) in aqueous acetic acid results in the formation
of the corresponding carbonyl compounds and ammonia. The reaction is first order with respect to TBATB. Michaelis-Menten type
kinetics is observed with some of the amino acids while others exhibit second-order dependence. It failed to induce polymerization
of acrylonitrile. The effect of solvent composition indicate that the rate of reaction increases with increase in the polarity
of the medium. Addition of tetrabutylammonium chloride has no effect on the rate of oxidation. Addition of bromide ion causes
decrease in the oxidation rate but only to a limiting value. The reaction is susceptible to both polar and steric effects
of the substituents. A suitable mechanism has been proposed 相似文献
67.
N-Benzyl-DABCO tribromide, a stable, solid organic ammonium tribromide, has been used as a bromine source for the regioselective and high-yielding bromination of aromatic amines and phenols. Mono-bromination proceeds well in the presence of a stoichiometric amount of bromine source at room temperature. 相似文献
68.
An efficient and mild system for protection of a variety of alcohols with 3,4‐dihydro‐2H‐pyran (DHP) in the presence of catalytic amounts of benzyltriphenylphosphonium tribromide (BTPTB) (1) gives the corresponding tetrahydropyan ethers (ROTHP) in dichloromethane. The experimental procedure is simple, and the products are straightforwardly isolated in high to excellent yields. 相似文献
69.
A facile method for the benzylic bromination of toluene derivatives was developed. Various substituted toluenes were brominated with boron tribromide as bromine source in carbon tetrachloride at room temperature, affording their corresponding benzyl bromides in good yields. 相似文献
70.
Firouz Matloubi Moghaddam Hassan Zali Boeini Dordaneh Zargarani Ghasem Rezanejad Bardajee 《合成通讯》2013,43(8):1093-1096
N‐Benzyl‐DABCO‐ammonium tribromide was found to be an efficient and recyclable reagent for the deprotection of dithioacetals in dichloromethane/methanol at room temperature. The reaction can be performed cleanly, in short time, and in high yield. 相似文献