N.M.R. and absorption spectra of nitrotoluidines

Abstract

N.m.r. chemical shifts of ring protons and absorption spectra of 4-substituted 2-nitroaniline deriva- tives were investigated. It was ascertained that the rotations of dimethylamino and/or 2-nitro groups are influenced by the resonance interaction of the dimethylamino group with 4-substituents and the C₁ → C₂ absorption band is displaced bathochromically by resonance saturation with 4-substituents. The long-range coupling of NH with H5 in N-methyl-2-nitro-p-toluidine was found to be absent and it is considered that the intramolecular hydrogen bonding of amino hydrogen with the 2-nitro group is ruptured by ROH and polar solvents.