Rapid scan spectrophotometric and kinetic studies in the reactions of 4-substituted-2,6-dinitro-N-n-butylanilines with n-butylamine in dimethyl sulfoxide

Abstract

The reactions of 2,4,6-trinitro-N-n-butylaniline 6a, 4-cyano-2,6-dinitro-N-n-butylaniline 6b and 4-methoxycarbonyl-2,6-dinitro-N-n-butylaniline 6c with n-butylamine in dimethyl sulfoxide have been investigated by rapid scan spectrophotometry and a stopped-flow method. 6a and 6b react competitively with n-butylamine to give the conjugate bases due to fast proton transfer and anionic σ-adducts by the addition of amine at the 3-position, while 6c reacts to give the conjugate base. The distinct spectra of only the conjugate bases have been observed. The effect of substituents on rate and equilibrium constants obtained for these competitive reactions is discussed.