Rapid Kinetics and Relative Reactivity of Some Five Membered Aromatic Heterocycles using Hydrodynamic Voltammetry

Walke, Sandhya B.; Bonde, S. L.; Bhadane, Ranjana P.; Dangat, V. T.; Jadhav, B.V.

doi:10.13005/ojc/310449

Cited by 2 publications

(4 citation statements)

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“…Imidazole, pyrazole, and thiazole are five‐membered aromatic heterocycles with two heteroatoms. Rate constants for the bromination of imidazole, pyrazole and thiazole by molecular bromine are reported as 88.63, 75.52, and 18.63 M −1 s −1 , respectively 9 . Thiazole contains sulfur as the heteroatom, which reduces the basicity of the thiazole ring more than imidazole and pyrazole 28 .…”

Section: Resultsmentioning

confidence: 99%

“…Rate constants for the bromination of imidazole, pyrazole and thiazole by molecular bromine are reported as 88.63, 75.52, and 18.63 M −1 s −1 , respectively. 9 sulfur as the heteroatom, which reduces the basicity of the thiazole ring more than imidazole and pyrazole. 28 Thiazole ring has larger d-electron delocalization and possesses greater aromaticity than imidazole and pyrazole.…”

Section: Relative Reactivity Of Substrates and Reagentsmentioning

confidence: 99%

“…8 The kinetics of bromination of five-membered aromatic heterocycles with two heteroatoms by molecular bromine and N-bromosuccinimide has been studied in the aqueous medium. 9 Nevertheless, the amount of relevant kinetic data of iodination reactions of five-membered aromatic heterocycles with two heteroatoms in aqueous medium is still quite limited. Hence, the study of the kinetics of the iodination reactions of five-membered aromatic heterocycles with two heteroatoms by viable iodinating reagents and a comparative study of the relative reactivity of the substrates as well as reagents is necessary.…”

Section: Introductionmentioning

confidence: 99%

“…For the iodination of pyrrole in aqueous medium at 30°C rate constant reported was 5000 M −1 s −1 8 . The kinetics of bromination of five‐membered aromatic heterocycles with two heteroatoms by molecular bromine and N ‐bromosuccinimide has been studied in the aqueous medium 9 . Nevertheless, the amount of relevant kinetic data of iodination reactions of five‐membered aromatic heterocycles with two heteroatoms in aqueous medium is still quite limited.…”

Section: Introductionmentioning

confidence: 99%

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Comparative quantitative kinetic study of rapid iodination of thiazole and its methyl derivatives in aqueous medium

Kad

Bhadane

Walke

2022

Int J of Chemical Kinetics

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The study provides a quantitative framework for the assessment of the relative reactivity of thiazole and its two methyl derivatives namely 2-methylthiazole and 4-methylthiazole towards iodination reaction. Thiazole and its derivatives have a wide range of industrial and medicinal applications attributed to the ability of thiazole to manifest substituents around the core scaffold. The kinetic study of the iodination reactions of these substrates helps in the above applications since kinetics is an important investigational tool in configuring the mechanism of the reaction. In the present work, molecular iodine (I 2 ) and iodine monochloride (ICl) were used as reagents for the iodination of thiazole, 2-methylthiazole, and 4-methylthiazole in aqueous medium. The iodination reactions are rapid electrophilic substitution reactions and hence special technique known as hydrodynamic voltammetry was employed for the kinetic study. Iodine is the only electro-reducible species in the reactions. As the solution is devoid of iodide ions, a decrease in the concentration of iodine is measured in terms of diffusion current using a rotating platinum electrode with a saturated calomel electrode (SCE) as a reference electrode. The reactivity correlation of substrates towards iodination reaction was quantitively assessed by determining the reaction rate constants and thermodynamic parameters. The study shows overall rate of iodination of 4-methylthiazole is faster than 2-methylthiazole which is faster than thiazole. The study helps to develop a mechanistic approach considering the effect of substituent present on the thiazole ring. The order of reactivity of the reagents was determined based on obtained rate constants and explained owing to the nature of the reagent.

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Section: Resultsmentioning

confidence: 99%

Section: Relative Reactivity Of Substrates and Reagentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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