Mechanism of Oxidation of the Antituberculosis Drug Isoniazid by Bromate in Aqueous Hydrochloric Acid Medium

Yalgudre, R S; Gokavi, Gavisiddappa S.

doi:10.1021/ie203058s

Cited by 14 publications

(2 citation statements)

References 19 publications

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“…Diazene further oxidizes to dinitrogen and water with another mole of Cr(VI). Yalgudre and Gokavi , while investigating the oxidation of isoniazid by bromate in aqueous hydrochloric acid medium, demonstrated the formation dinitrogen and water from diazene intermediate. The formation of unstable diazene intermediate in the oxidation of isoniazid has also been reported by Bodiguel et al .…”

Section: Resultsmentioning

confidence: 99%

Oxidation of Antitubercular Drug Isoniazid by a Lipopathic Oxidant, Cetyltrimethylammonium Dichromate: A Mechanistic Study

Garnayak

Patel

2015

Int. J. Chem. Kinet.

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The oxidation of an antitubercular drug isoniazid by a lipopathic oxidant cetyltrimethylammonium dichromate (CTADC) in a nonpolar medium generates isonicotinic acid both in the presence and the absence of acetic acid. The conventional UV–vis spectrophotometric method is used to study the reaction kinetics. The occurrence of the Michaelis–Menten–type kinetics with respect to isoniazid confirms the binding of oxidant and substrate to form a complex before the rate‐determining step. The existence of the inverse solvent kinetic isotope effect, k(H2O)/ k(D2O) = 0.7, in an acid‐catalyzed reaction proposes a multistep reaction mechanism. A decrease in the rate constant with an increase in [CTADC] reveals the formation of reverse micellar–type aggregates of CTADC in nonpolar solvents. In the presence of different ionic and nonionic surfactants, CTADC forms mixed aggregates and controls the reaction due to the charge on the interface and also due to partition of oxidant and substrate in two different domains. High negative entropy of activation (ΔS‡ = –145 and –159 J K−1 mol−1 in the absence and presence of acetic acid) proposes a more ordered and highly solvated transition state than the reactants. Furthermore, the solvent polarity‐reactivity relationship reveals (i) the presence of less polar and less ionic transition state compared to the reactants during the oxidation, (ii) differential contribution from nonpolar and dipolar aprotic solvents toward the reaction process, and (iii) the existence of polarity/hydrophobic switch at log P = 0.73. A suitable mechanism has been proposed on the basis of experimental results. These results may provide insight into the mechanism of isoniazid oxidation in hydrophobic environment and may assist in understanding the drug resistance in different location.

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Section: Resultsmentioning

confidence: 99%

Oxidation of Antitubercular Drug Isoniazid by a Lipopathic Oxidant, Cetyltrimethylammonium Dichromate: A Mechanistic Study

Garnayak

Patel

2015

Int. J. Chem. Kinet.

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“…After the removal of the organic products, the presence of green colored residue in the reaction mixture supports the reduction of Cr(VI) to Cr(III) . The possibility of a free radical mechanism was ruled out because of the following: (i) no precipitate was observed by addition of acrylonitrile to the reaction mixture; − (ii) there is no signal in the EPR spectrum; (iii) the addition of acrylonitrile does not have any effect on the rate of reaction.…”

Section: Results and Discussionmentioning

confidence: 99%

Oxidation of Epinephrine to Adrenochrome by Cetyltrimethylammonium Dichromate: A Mechanistic Study

Garnayak

Patel

2014

Ind. Eng. Chem. Res.

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The present study reports the oxidation of epinephrine (adrenaline), a neurotransmitter by a lipid compatible lipophilic Cr (VI) oxidant, cetyltrimethylammonium dichromate (CTADC). The kinetics of the reaction is studied in organic media in the presence of acetic acid by UV–vis spectroscopic method. The rate of the reaction is measured by monitoring adrenochrome, the oxidized product of epinephrine at 455 nm. The reaction is fractional order with respect to CTADC and epinephrine. Acetic acid is found to retard the rate of the reaction. A suitable ionic mechanism is proposed based on the experimental findings where epinephrine is converted to adrenochrome through the intermediate, leucochrome. The proposed reaction mechanism is also supported by the effect of solvent, effect of temperature, and effect of surfactants on the rate of the reaction. The decrease in rate constant due to increase in polarity and hydrogen bond acceptor ability of the solvent indicates the existence of a less polar transition state and stabilization of the reactants through strong intermolecular hydrogen bonding. The addition of surfactants (cationic, anionic, and nonionic) decreased the rate of reaction, and the retardation is explained through the partition of oxidant and substrate in different microheterogeneous media.

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Chemometric challenges in development of paper-based analytical devices: Optimization and image processing

Hamedpour

Oliveri

Leardi

et al. 2020

Analytica Chimica Acta

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Mechanism of Oxidation of the Antituberculosis Drug Isoniazid by Bromate in Aqueous Hydrochloric Acid Medium

Cited by 14 publications

References 19 publications

Oxidation of Antitubercular Drug Isoniazid by a Lipopathic Oxidant, Cetyltrimethylammonium Dichromate: A Mechanistic Study

Oxidation of Antitubercular Drug Isoniazid by a Lipopathic Oxidant, Cetyltrimethylammonium Dichromate: A Mechanistic Study

Oxidation of Epinephrine to Adrenochrome by Cetyltrimethylammonium Dichromate: A Mechanistic Study

Chemometric challenges in development of paper-based analytical devices: Optimization and image processing

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