Electronic and solvent effects on kinetics of S_NAr substitution reactions of substituted anilines with 2,6-bis(trifluoromethanesulfonyl)-4-nitroanisole in MeOH-Me₂SO mixtures of varying composition: one reaction with two mechanistic pathways.

ABSTRACT:

Abstract

The kinetics and mechanism of the aromatic nucleophilic substitution reactions of 2,6-bis(trifluoromethanesulfonyl)-4-nitroanisole with para-X-substituted anilines (X = OH, OMe, Me, H, F, I, Cl) were studied in MeOH-Me₂SO mixtures and pure Me₂SO at 25.0 °C. The second-order rate coefficients depend on the substitutent in aniline and give good Hammett and Brønsted correlations; a polar S_NAr reaction is proposed for the reaction in different MeOH-Me₂SO mixtures. The measured rate coefficients of the reaction demonstrated dramatic variations for aniline donor with the increasing dimethyl sulfoxide composition in MeOH-Me₂SO mixtures. In this case, the Hammett and Brønsted plots are biphasic and concave upwards with

SUBMITTER: El Guesmi N 

PROVIDER: S-EPMC4495024 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature