Mechanism of acid bromate oxidation of trans mono-substituted cinnamic acids: structure reactivity correlation - a non-linear hammett's plot

Reddy, Ch. Sanjeeva; Sundaram, E. V.

doi:10.1016/s0040-4020(01)80072-7

Cited by 23 publications

(4 citation statements)

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“…In contradiction, nonlinear concave upward Hammett plots were observed in the oxidative decarboxylation of PSAA [ 13 ] and sulfoxidation of PMAA [ 14 ] by [oxo(salen)chromium(V) + ] complexes in the presence of ligand oxides; oxidative decarboxylation of PSAA by iron (III) polypyridyl complexes [ 38 ] ; oxidation of substituted trans‐cinnamic acids by pyridinium chlorochromate, [ 103 ] chloramines, [ 104 ] and acid bromate [ 105 ] ; oxygen atom transfer reaction of axially ligated Mn(V)oxo complexes [ 106 ] ; and stereoselective catalytic sulfoxidations mediated by titanium and zirconium trialkylanolamine complexes. [ 107 ]…”

Section: Resultsmentioning

confidence: 99%

“…Similar nonlinear concave downward Hammett plots were reported during the oxidation of anils by isonicotinium dichromate, [96] conversion of rhenium azides to imido complexes, [97] nucleophilic substitution reactions between N-methyl-α-bromoacetanilides and benzylamines, [98] reaction of β-benzoylamines with pseudomonas fluorescens kynureninase, [99] pyridinolysis of methyl phenyl phosphinic chloride, [100] oxidation of sulfides with pyridinium dichromate, [101] and vanadium catalyzed sulfoxidation. [102] In contradiction, nonlinear concave upward Hammett plots were observed in the oxidative decarboxylation of PSAA [13] and sulfoxidation of PMAA [14] by [oxo(salen) chromium(V) + ] complexes in the presence of ligand oxides; oxidative decarboxylation of PSAA by iron (III) polypyridyl complexes [38] ; oxidation of substituted transcinnamic acids by pyridinium chlorochromate, [103] chloramines, [104] and acid bromate [105] ; oxygen atom transfer reaction of axially ligated Mn(V)oxo complexes [106] ; and stereoselective catalytic sulfoxidations mediated by titanium and zirconium trialkylanolamine complexes. [107]…”

Section: Substituent Effects and Hammett Correlationmentioning

confidence: 99%

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Impact of added ligand oxides in the sulfoxidation of phenylmercaptoacetic acids with oxovanadium(IV)‐salen complexes

Kavitha¹,

Subramaniam

2023

J of Physical Organic Chem

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The mechanistic aspects covering the effect of added ligand oxides, picoline N-oxide (PicNO), pyridine N-oxide (PyNO), and triphenyl phosphine oxide (TPPO) on the selective sulfoxidation of phenylmercaptoacetic acids to PSAA by H 2 O 2 catalyzed by oxovanadium(IV)-salen complexes have been studied spectrophotometrically in 100% acetonitrile medium. Hydroperoxovanadium(V)-salen is the reactive species in this sulfoxidation.The rate of sulfoxidation is found to be enhanced significantly by increasing the concentrations of PMAA, salen, and H 2 O 2 . The ascertained order of reactivity among the oxovanadium(IV)-salen complexes is 5,5 0dimethyl > unsubstituted salen > 5,5 0 -dichloro. The reaction is found to be impeded by the addition of ligand oxide and introduction of substituents in PMAA. The observed order of rate retardation among ligand oxides is TPPO < PyNO < PicNO. Downward Hammett plot obtained has been rationalized by change in rate-determining step from coordination of PMAA to active species for electron-withdrawing substituents to transfer of oxygen to PMAA for electron-donating substituents within the same mechanism.

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Section: Resultsmentioning

confidence: 99%

Section: Substituent Effects and Hammett Correlationmentioning

confidence: 99%

Impact of added ligand oxides in the sulfoxidation of phenylmercaptoacetic acids with oxovanadium(IV)‐salen complexes

Kavitha¹,

Subramaniam

2023

J of Physical Organic Chem

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“…Bromate then reacts with the binary complex C 1 , giving a cyclic bromate ester (ternary complex C 2 ). The concerted cis 1,3-cycloaddition of BrO 3 -to the carbon-carbon double bond of the substrate has also been proposed in the bromate oxidation of cinnamic acids [27] and in the pyridinium fluorochromate oxidation of 4-oxo acids [28]. Ru(III) ene p-complex formation enhances the reactivity of the C=C of complex C 1 to form the cyclic bromate ester.…”

Section: Reaction Mechanismmentioning

confidence: 99%

Aquachlororuthenium(III) catalysis in the oxidation of substituted 4-oxo-4-arylbutanoic acids by bromate in acid medium: a kinetic and mechanistic study and validity of linear free-energy relationships

Manjari

Reddy

2011

Transition Met Chem

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Ru(III) acts an efficient catalyst in the oxidation of substituted 4-oxo-4-arylbutanoic acids (4-oxo acids) by bromate in sulfuric acid medium, giving the corresponding benzoic acids in quantitative yields. The reaction shows first-order dependence in both [bromate] and [H 2 SO 4 ], and a non-linear dependence on both [oxo acid] and [catalyst]. Changing solvent from H 2 O to D 2 O increases the rate. The rate is not affected by ionic strength but decreases with increase in dielectric constant of the medium. Electron-releasing substituents in the phenyl ring of the substrate greatly accelerate the rate, whereas the retardation by electron-withdrawing substituents, though perceptible, is small. The linear free-energy relationship is characterized by smooth curves in Hammett plots of log k versus r; however, linear plots are obtained with excellent correlation coefficients at all the studied temperatures, when Brown's r ? values are used. The reaction constant is negative and decreases with increase in temperature. From the intersection of the lines in the Hammett and Arrhenius plots, the isokinetic relationship is evaluated. A mechanism involving a cyclic oxidant-substrate-catalyst ternary complex is proposed, in which both C-C bond-breaking and C-O bond formation are involved, and the oxidation state of Ru(III) remains unchanged. A rate law explaining all the kinetic results has been derived and verified. The reaction is an example of neighboring group participation in intramolecular catalysis and is potentially useful for the synthesis of substituted benzoic acids.

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“…Potassium bromate is used for oxidation of uncatalyzed reactions by several workers. [28][29] Uncatalyzed reactions of aldoses and aldosamines [30] , carbohydrates [31] compound oxidation by potassium bromate has also been reported. Ir(III) catalyzed cyclicalcohols [32] , cyclic ketones [33] oxidation by potassium bromate has also been reported.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic properties and Mechanism of Aquachloro iridium (III) Catalyzed Oxidation of Pharmaceutical drug (Paracetamol) by Acidic solution of Potassium Bromate (KBrO3): A kinetic study

Patel¹

2018

IJRASET

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Mechanism of acid bromate oxidation of trans mono-substituted cinnamic acids: structure reactivity correlation - a non-linear hammett's plot

Cited by 23 publications

References 24 publications

Impact of added ligand oxides in the sulfoxidation of phenylmercaptoacetic acids with oxovanadium(IV)‐salen complexes

Impact of added ligand oxides in the sulfoxidation of phenylmercaptoacetic acids with oxovanadium(IV)‐salen complexes

Aquachlororuthenium(III) catalysis in the oxidation of substituted 4-oxo-4-arylbutanoic acids by bromate in acid medium: a kinetic and mechanistic study and validity of linear free-energy relationships

Thermodynamic properties and Mechanism of Aquachloro iridium (III) Catalyzed Oxidation of Pharmaceutical drug (Paracetamol) by Acidic solution of Potassium Bromate (KBrO3): A kinetic study

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