Arylsulfonylation of N-isobutylaniline and its derivatives: experimental study and quantum-chemical calculations

Abstract

The kinetics of the reactions of benzene-substituted N-isobutylanilines 1a—h with 3-nitrobenzenesulfonyl chloride in propan-2-ol was studied at 298 K. To analyze the reactivities of compounds 1a—h in the arylsulfonylation reactions and substantiate the possible mechanism of these reactions, the geometric, electronic, and energy characteristics of the reagents and a series of model compounds were calculated by the semiempirical quantum-chemical AM1 and PM3 methods. The rate of arylsulfonylation of N-isobutylaniline and its derivatives increases directly proportional to the contributions of the s and p z orbitals of the N atoms to HOMO of amine and of the S atoms to LUMO of sulfonyl chloride. The coefficients of these AOs can be considered as the reactivity indices of the reagents used for arylsulfonylation of substituted N-isobutylanilines with aromatic sulfonyl chlorides. It was proposed that the reaction under study is orbital-controlled.