The rates of tautomerization of 2-nitrocyclohexanone (2-NCH) have been measured spectrophotometrically at 25.0 +/- 0.1 degrees C in several organic aprotic solvents and their binary mixtures. In cyclohexane the reaction is effectively catalyzed by bases and inhibited by acids while the so-called "spontaneous reaction" appears essentially due to autocatalysis. Apparent second order rate constant...

2-Keto-3-methylvaleric acid (KMVA) has been found not to undergo spontaneous keto-enol tautomerization in neutral aqueous solution, alone or in the presence of large concentrations of pyridoxamine or pyridoxamine-5-phosphate. This finding denies the commonly held suppositions that 3R-KMVA is derived spontaneously from 3S-KMVA in vivo, and that L-alloisoleucine is the product of the reamination ...

The effect of Ni(II), Cu(II) and Zn(II) association on the diketo/keto-enol tautomerism of thymine has been investigated through the use of B3LYP density functional theory calculations. Final energies were obtained at the B3LYP/6-311+G(2df,2p)//B3LYP/6-311+G(d,p) level of theory. Ni(II) and Cu(II) lead to an oxidation of thymine which for Zn(ii) is only partial and catalyze the tautomerization ...

Curcuminoids are a safe natural food coloring additive with anti-inflammatory, antioxidant, and anticarcinogenic activities. Although demethoxycurcumin is one of the major bioactive constituents of curcuminoids, knowledge about its metabolic fate is scant. In the present study, four new metabolites, 5-dehydroxy-hexahydro-demethoxycurcumin-A (M-1), 5-dehydroxy-hexahydro-demethoxycurcumin-B (M-2)...

In combustion, enols can undergo keto-enol tautomerizations, which are intermediate steps in the formation of pollutant species. this work, we performed a theoretical kinetic study step-wise propen-2-ol tautomerization catalyzed by hydrogen and hydroperoxyl radicals. Ab initio calculations at CCSD(T)/aug-cc-pVTZ//M06-2X/cc-pVTZ level were run, rate constants calculated using multistructural tor...

Abstract The formation of complex organic molecules by simulated secondary electrons generated in the track galactic cosmic rays was investigated interstellar ice analogs composed methanol and carbon dioxide. processed ices were subjected to temperature-programmed desorption mimic transition a cold molecular cloud warmer star-forming region. Reaction products detected as they sublime using phot...

Single walled nanotubes (SWNT) are common interested nanovehicle to make biosensors more sensitive.Carbon nanotubes (CNTs) have many distinct properties make them to be exploited to develop the nextgeneration of such nano sensors .The Keto-Enol tautomerization is one of the most common investigatedsubjects of isomerism in this regards, sensors are devices that are able to detect and change the ...

γ-Valerolactone (GVL) is readily accessible by catalytic hydrogenation of carbohydrate-derived levulinic acid (LA) and an attractive biobased chemical with a wide range applications in both the (e.g., as biomass-derived solvent) transportation fuel sector. In this study, we used isotopic labeling experiments to provide insights into pathways involved conversion LA GVL under different reaction c...