- Synthesis, structural characterization, and antioxidant activities of 2,4-dinitrophenyl-hydrazone derivatives
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Thirty-two derivatives of 2,4-dinitro phenylhydrazone 1-32 were synthesized by one step reaction and characterized by spectroscopic techniques such as EI-MS and 1H-NMR. Compounds 1-32 were screened for their in vitro antioxidant activities. DPPH radical s
- Ahad, Ghulam,Khan, Momin,Khan, Asif,Ibrahim, Mohammad,Salar, Uzma,Kanwal,Khan, Khalid Mohammed,Perveen, Shahnaz
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p. 961 - 973
(2018/10/02)
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- Structure-Reactivity correlation in the oxidation of substituted benzaldehydes by tetraethylammonium chlorochromate
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Oxidation of 36 monosubstituted benzaldehydes by tetraethylammonium chlorochromate in dimethyl sulphoxide, leads to the formation of corresponding benzoic acids. The reaction is of first order with respect to chlorochromate and aldehydes. The reaction is promoted by H+; the H+ dependence has the form kobs = a + b[H+]. The oxidation of duteriated benzaldehyde exhibits substantial primary kinetic isotope effect. The reaction was studied in 19 different organic solvents and the effect of solvent was analyzed using Taft's and Swain's multiparametric equations. The rates of the oxidation of para- and meta-substituted benzaldehydes showed excellent correlation in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes were correlated well with tetraperametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalized effect than is the oxidation of ortho- and meta- substituted compounds, which display a greater dependence on the field effect. The positive value of h suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the orthosubstituents. A suitable mechanism has been proposed.
- Gehlot,Prasadrao,Sharma
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experimental part
p. 1173 - 1178
(2012/01/05)
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- Kinetics and Mechanism of the Oxidation of Substituted Benzylamines by N-Chlorosuccinimide
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The oxidation of ortho-, meta-, and para-substituted benzylamines by N-chlorosuccinimide (NCS), to the corresponding benzaldehydes, is first-order with respect to NCS and the amine.The pH dependence of the reaction rate suggests that the unprotonated benzylamine is the reductant.There is no effect of added succinimide.NCS itself has been postulated as the reactive oxidising species.The oxidation of benzylamine exhibited a substantial primary kinetic isotope effect (kH/kD=6.20).The rates of oxidation of the meta- and para-substituted benzylamines were separately correlated in Taft and Swain's dual substituent parameter equations.For the para-substituted compounds, the best correlation is obtained with ?I and ?R+ values; meta-substituted compounds correlate with ?I and ?R0 values.The reaction constants have negative values.The oxidation rates of the ortho-substituted compounds yield an excellent correlation in a triparametric equation involving Taft's ?I and ?R+ values and Charton's steric parameter, V.A mechanism involving transfer of a hydride ion from the amine to the oxidant in the rate-determining step is proposed.
- Banerji, Kalyan K.
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p. 1015 - 1020
(2007/10/02)
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- Preparation and Use of Tetra-n-butylammonium Per-ruthenate (TBAP reagent) and Tetra-n-propylammonium Per-ruthenate (TPAP reagent) as New Catalytic Oxidants for Alcohols
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Tetra-n-butylammonium per-ruthenate (Bun4N)(RuO4) and tetra-n-propylammonium per-ruthenate (Prn4N)(RuO4), with N-methylmorpholine N-oxide, function as mild catalitic oxidants for the high yield conversion of alcohols to aldehydes and ketones and are competitive with more conventional reagents.
- Griffith, William P.,Ley, Steven V.,Whitcombe, Gwynne P.,White, Andrew D.
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p. 1625 - 1627
(2007/10/02)
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- A New Ring Opening Reaction of N-Aminophthalimide Hydrazones
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Araldehyde hydrazones III of N-aminophthalimide underwent rapid ring opening reactions initiated by the addition of excess base to their refluxing methanolic solutions.The products were conveniently isolated through liquid-liquid extraction as the stable
- Hearn, Michael J.,Rosenberg, Judith,Campbell, Mary L.
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p. 1405 - 1407
(2007/10/02)
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