The azines of acetophenone and its mono-and di-chlorinated derivatives show a bathochronic shift in the yellow region, but the azine of trichloroacetophenone is colorless. Similar trends are observed in the brominated analogs and in the chlorinated propiophenone azines. The colorless tétrachloropropiophénone azine (13) is shown by X- ray analysis to be nonplanar at the azine atoms (NN torsion angle, 126.7°). ...
