SUBSTITUENT EFFECTS ON THE RATE OF CHLORINATION OF ANILINE BY LORO-T(3)-METHYL-R(2),C(6)-DIPHENYLPIPERIDIN-4-ONE

Chlorination of aniline by N-chloro-t(3)-methyl-r(2), c(6)-diphenylpip eridin-4-one (NCP) in aqueous ethanol in presence of H+ is a second or der reaction and is independent of [H+]. Kinetic results suggest proto nated NCP as the reactive species and the site of attack as amino N-at om. The reaction rates of 18 para-, meta- and ortho-substituted anilin es have been measured and the structure-reactivity relationship is ana lyzed. The effect of para-substituents is governed by sigma(I) (48%) a nd sigma(R)(+) (52%) with negative reaction constants. In the reaction of ortho-substituted anilines, field, resonance and steric effects op erate at 53, 21 and 26%, respectively, and the orientation of the orth o carboxyl group is orthogonal.