Palladium(II) Catalysed Oxidation of l-proline by Heptavalent Manganese in Aqueous Alkaline Medium: A Free Radical Intervention and Decarboxylation

Seregar, Veeresh; Hiremath, Chanabasayya V.; Nandibewoor, Sharanappa T.

doi:10.1007/s11243-006-0029-x

Cited by 13 publications

(12 citation statements)

References 28 publications

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“…2); from the intercepts and slopes of such plots, the reaction constants K 1 , K 2 , K 4 and k 2 were calculated as (0.52 ± 0.022) dm 3 mol -1 , (6.12 ± 0.25) 9 10 -4 mol dm -3 , (1.25 ± 0.055) 9 10 3 dm 3 mol -1 , (4.93 ± 2.0) 9 10 4 dm 3 mol -1 s -1 , respectively. The values of K 1 and K 2 obtained are in good agreement with previously reported values [37,38]. These constants were used to calculate the rate constants and compared with the experimental k C values and found to be in reasonable agreement with each other, which fortifies the Scheme 2.…”

Section: Ossupporting

confidence: 88%

“…In the pre rate determining stage, the hydroxylated species of Ru(III) combines with a molecule of anionic form of GBP to give an intermediate complex, which further reacts with one mole of MPA in a slow step to give anionic free radical with formation of Ag(II) species and regeneration of catalyst, ruthenium(III), this anionic free radical further reacts with Ag(II) in a fast step to yield the products. The formation of anionic free radical is also supported in earlier work [37,38]. The experimental results can be accommodated in Scheme 1.…”

Section: Mechanism Of Ru(iii) Catalysissupporting

confidence: 75%

“…Such a complex between a substrate and a catalyst has been observed in other studies [37,38]. The rate law (8) for the Scheme 1 could be derived as…”

Section: Mechanism Of Ru(iii) Catalysissupporting

confidence: 57%

“…However, the Lineweaver-Burk plot proved the complex formation between catalyst and reductant, which explains less than unit order in [GBP]. Such a complex between a substrate and a catalyst has been observed in other studies [37,38]. The rate law (10) for the Scheme 2 could be derived as, Eq.…”

Section: Osmentioning

confidence: 89%

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Ru(III)/Os(VIII) Catalysed Oxidation of Gabapentin (Neurotin) Drug by Diperiodatoargentate(III) in Aqueous Alkaline Medium (Stopped Flow Technique): A Comparative Study

2009

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The kinetics of ruthenium(III) (Ru(III)) and osmium(VIII) (Os(VIII)) catalysed oxidation of neuroleptic drug, gabapentin (GBP) by diperiodatoargentate(III) (DPA) in alkaline medium at 27°C and a constant ionic strength of 0.60 mol dm -3 was studied spectrophotometrically. The oxidation products in both the cases are 1-(hydroxymethyl) cyclohexane acetic acid and Ag(I). The stoichiometry is the same in both the catalysed reactions i.e. [gabapentin]:[DPA] = 1:1. The reaction is of first order in Os(VIII)/ Ru(III) and [DPA] and has less than unit order in both [GBP] and [alkali]. The oxidation reaction in alkaline medium has been shown to proceed via a Os(VIII)/Ru(III)-gabapentin complex, which further reacts with one mole of monoperiodatoargentate(III) (MPA) species in a rate determining step followed by other fast steps to give the products. The main products were identified by spot test and spectroscopic studies. The reaction constants involved in the different steps of the mechanism are calculated. The catalytic constant (K c ) was also calculated for both catalysed reactions at different temperatures. From the plots of log K c versus 1/T, values of activation parameters with respect to the catalyst have been evaluated. The activation parameters with respect to slow step of the mechanism are computed and discussed and thermodynamic quantities are also determined. It has been observed that the catalytic efficiency for the present reaction is in the order of Os(VIII)[Ru(III). The probable active species of catalyst and oxidant have been identified.

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Section: Ossupporting

confidence: 88%

Section: Mechanism Of Ru(iii) Catalysissupporting

confidence: 75%

“…Such a complex between a substrate and a catalyst has been observed in other studies [37,38]. The rate law (8) for the Scheme 1 could be derived as…”

Section: Mechanism Of Ru(iii) Catalysissupporting

confidence: 57%

Section: Osmentioning

confidence: 89%

See 2 more Smart Citations

Ru(III)/Os(VIII) Catalysed Oxidation of Gabapentin (Neurotin) Drug by Diperiodatoargentate(III) in Aqueous Alkaline Medium (Stopped Flow Technique): A Comparative Study

2009

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“…The permanganate species then reacts with aspirin in its anionic form to give a complex (C), which decomposes in a slow step to give a free radical of salicylate ion and acetate ion. Such type of anionic free radicals have been reported in the literature [16]. This anionic free radical of salicylate ion then reacts with three more molecules of permanganate in further fast steps to yield the product 1,4-benzoquinone 2-carboxylate ion as given in Scheme 1.…”

Section: Discussionmentioning

confidence: 71%

Mechanistic and spectroscopic investigations of oxidative degradation of aspirin by aqueous alkaline permanganate

Veeresh

Lamani

Nandibewoor

2009

Transition Met Chem

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The kinetics of oxidation of aspirin (ASP) by permanganate in alkaline medium at a constant ionic strength of 0.06 mol dm -3 was studied spectrophotometrically using a rapid kinetic accessory. The reaction between permanganate and aspirin in alkaline medium exhibited 1:4 stoichiometry (aspirin: permanganate). The reaction was of first order in [permanganate ion] and had less than unit order in both [ASP] and [alkali]. A decrease in the dielectric constant of the medium decreased the rate of reaction. The effect of added products and ionic strength of the reaction medium have been investigated. The oxidation reaction in alkaline medium has been shown to proceed via a permanganate-aspirin complex, which decomposes slowly in a rate determining step followed by other fast steps to give the products. The main products were identified by spot test and spectroscopic studies. A suitable mechanism is proposed. The reaction constants involved in the different steps of the mechanism were derived. The activation parameters with respect to the slow step of the mechanism were computed and discussed and thermodynamic quantities were also determined.

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Chloride and iodide mediated oxidation of antimony(III) by cerium(IV) in aqueous sulphuric acid medium

Thabaj

Munavalli

Chimatadar

et al. 2007

Transition Met Chem

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The micro amounts of iodide (10 )7 ) (mol dm )3 ) and chloride (10 )2 ) (mol dm )3 ) mediated oxidation of antimony(III) by cerium(IV) in an aqueous sulphuric acid medium have been studied spectrophotometrically at 25°C and l = 3.10 mol dm )3 . The stoichiometry is 1:2 in chloride and iodide mediated reactions. i.e. one mole of antimony(III) requires two moles of cerium(IV). In the case of chloride mediated reaction, the reaction was first order in cerium(IV) and halide concentrations, whereas in the case of iodide mediated reaction the order with respect to [cerium(IV)] was unity and with respect to iodide concentrations was more than unity (ca. 1.4). In both chloride and iodide mediated reactions the order with respect to antimony(III) concentrations was less than unity. Increase in sulphuric acid concentration increased the rate. The order with respect to H + ion concentration was less than unity. Added products, cerium(III) and antimony(V) did not have any significant effect on the reaction rate. The active species of oxidant was understood to be H 3 CeðSO 4 Þ À 4 , whereas that of reductant as SbCl 3 in the case of chloride and SbI 2þ in case of iodide mediated reactions. The possible reaction mechanisms were proposed and the activation parameters were determined and discussed.

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Palladium(II) Catalysed Oxidation of l-proline by Heptavalent Manganese in Aqueous Alkaline Medium: A Free Radical Intervention and Decarboxylation

Cited by 13 publications

References 28 publications

Ru(III)/Os(VIII) Catalysed Oxidation of Gabapentin (Neurotin) Drug by Diperiodatoargentate(III) in Aqueous Alkaline Medium (Stopped Flow Technique): A Comparative Study

Ru(III)/Os(VIII) Catalysed Oxidation of Gabapentin (Neurotin) Drug by Diperiodatoargentate(III) in Aqueous Alkaline Medium (Stopped Flow Technique): A Comparative Study

Mechanistic and spectroscopic investigations of oxidative degradation of aspirin by aqueous alkaline permanganate

Chloride and iodide mediated oxidation of antimony(III) by cerium(IV) in aqueous sulphuric acid medium

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