نتایج جستجو برای: enol tautomerism
تعداد نتایج: 1924 فیلتر نتایج به سال:
The present paper describes a new enzyme from animal tissues which catalyzes the keto-enol tautomeriaation of the phenylpyruvic acids. Preliminary accounts of this tautomerase have been published (1, 2). The enzyme has not yet proved to be essential in any biological reaction, but a physiological role may be expected since specific tautomers of a-keto acids are substrates or products in some re...
The 1H chemical shifts of benzaldehyde, 2-chloro-, 2-hydroxyand 2-methoxybenzaldehyde, acetophenone, 2-methoxyand 2-hydroxyacetophenone, indanone, anthraquinone, fluorenone, anthrone,a-tetralone, 2,4,6trimethylacetophenone, 9-acetylanthracene, 9-anthranaldehyde and benzosuberone were obtained and completely assigned in CDCl3 and DMSO solution. In anthrone a keto–enol tautomerism (anthrone–9hydr...
Unprecedented alkylation of silyl enol ethers has been developed by the use of ortho-alkynylbenzoic acid alkyl esters as alkylating agents in the presence of a gold catalyst. The reaction probably proceeds through the gold-induced in situ construction of leaving groups and subsequent nucleophilic attack on the silyl enol ethers. The generated leaving compound abstracts a proton to regenerate th...
A ferrocene-functionalised ureidopyrimidinone has been synthesised that can signal the solvent-induced tautomerism of the dimeric 4[1H]-pyrimidinone form to the monomeric 6[1H]-pyrimidinone form.
Studies of the non-enzymatic decarboxylation of /3-keto acids have shown that it is the keto form of the 8-keto acid which loses CO2 to form an enol of the product. This was demonstrated for dimethylacetoacetic acid by Pedersen (1) and for dimethyloxalacetic acid by Steinberger and Westheimer (2). These latter authors studied the catalytic effect of metal ions on the decarboxylation reaction an...
Kinetics of enol generation from propene has been predicted in an effort to understand the presence of enols in flames. A potential energy surface for reaction of OH with propene was computed by CCSD(T)/cc-pVDZ//B3LYP/cc-pVTZ calculations. Rate constants of different product channels and branching ratios were then calculated using the Master Equation formulation (J. Phys. Chem. A 2006, 110, 105...
For molecules with mobile hydrogen atoms, the result of quantitative structure-activity relationships (QSARs) as well as quantum chemical geometry optimisation depends on the position of the respective hydrogen atoms. Thus to obtain reliable results, tautomerism needs to be taken into account. With our in-house software ChemProp, we set up four different kinds of tautomerism and generated the t...
In a combined study on the photophysics of 2-(2'-hydroxyphenyl)-benzothiazole (HBT) in polar acetonitrile utilizing ultrafast infrared spectroscopy and quantum chemical calculations, we show that a branching of reaction pathways occurs on femtosecond time scales. Apart from the excited-state intramolecular hydrogen transfer (ESIHT) converting electronically excited enol tautomer into the keto t...
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