Synthesis and Characterization of 4′-Amino and 4′-Nitro Derivatives of 4-N,N-Dimethylaminotriphenylmethane as Precursors for a Proximate Malachite Green Metabolite

This paper describes the preparation of 4′-amino (2) and 4′-nitro (3) derivatives of 4-N,N-dimethylaminotriphenylmethane as precursors for presumed DNA-binding metabolites of malachite green. The primary amine 2 was synthesized via a condensation of 4-lithiated bis-(N,N-trimethylsilyl)aniline and 4-(dimethylamino)benzophenone. A simple nitro-dediazoniation reaction of 2 failed to afford 3, but gave exclusively a mixture derived from hydro-dediazoniation followed by nitration and N-dealkylative-N-nitrosation. Direct nitration of N,N-dimethylaminotriphenylmethane, however, afforded 3 as well as other nitro isomers.