Kinetic Study of the Reaction of Benzofuroxans with 2-Acetylthiophene: Effect of the Substituents on the Reaction Rate Using Hammett Equation

Damra Elhaj Mustafa, Intisar Salih Ahmed


The present work reports kinetic study of the reaction of benzofuroxan and its derivatives with 2-acetylthiophene. Hammett equation was used to determine the rate of the reaction and substituent effect. Specifically, chloro, nitro and methyl substituted benzofuroxans react with α-carbonyl compounds to form a fungicidal product quinoxalines-di-N-oxide (phenazine N5, N10-dioxides). The effect of the benzofuroxan substituents on the reactivity was performed and monitored by a UV/Visible spectrophotometer. The rate constants of the benzofuroxan, 5-chlorobenzofuroxan, 4-nitrobenzofuroxan, 5-methylbenzofuroxan and 4,6-dinitrobenzofuroxan reactions were found to be 3.32x10-3, 4.24x10-3, 3.48x10-3, 8.03x10-3 and 9.41x10-3 min-1 respectively. Moreover, Log k/k0 against the substituent constant σ gave a linear relationship, which indicates positive effect of electron withdrawing substituent on the reaction. Therefore, the substituents have substantial effect on the reaction of benzofuroxans with 2-acetylthiophene.





2-acetylthiophene; benzofuroxan; Hammett equation; substituent effect

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Orbital: The Electronic Journal of Chemistry (e-ISSN 1984-6428) is a quarterly scientific journal published by the Institute of Chemistry of the Universidade Federal de Mato Grosso do Sul, Brazil. Orbital is a peer-reviewed, open-access journal.