Aromatic amines and their derivatives. Part 3. The synthesis and crystal structure of 4,4'-NN'-tetramethyl-NN'-dinitroso-2,2'-methylenedianiline

Abstract

The synthesis of 4,4',N,N'-tetramethyl-NN'-dinitroso-2,2'-methylenedianiline (1) by the route p-MeC₆H₄NH₂+ HCHO + OH^-→(p-MeC₆H₄NMe)₂CH₂(7b); (7b)+ acid at 70 °C→ 4,N-dimethyl-6-(N-methyl-p-toluidinomethyl)aniline (4b); (4b)+ acid at 130 °C →4,4,NN-tetramethyl-2,2'-methylenedianiline (3b); (3b)+ HNO₂→(1), is described. Aspects of the ¹H n.m.r. spectra of the above and related compounds are discussed. A crystal-structure analysis of compound (1) shows one of the N-nitroso-groups to be disordered with the endo-form being in preponderance (4 : 1) over the exo-form. The other N-nitroso-group is exclusively exo in the solid state. There is little or no resonance between the benzene ring and the nitroso-group attached to the ring, the two groups being almost perpendicular to each other. In one of the N-nitroso-groups, the nitrogen atom deviates significantly from the plane of the benzene ring to which it is attached. Both amide nitrogen atoms show some pyramidal character.