Synthesis and characterization of N-Chloro-o-nitroanilines

Abstract

Chlorine(1) oxide in carbon tetrachloride was found to be an effective reagent for N-chlorinating 2-nitroanilines. These N-chloro-2-nitroanilines are sufficiently stable in solution at 20º to be characterized by reduction and by proton n.m.r, and infrared spectra. The infrared N-H stretching frequencies fall near the low value of 3330 cm^-1, apparently because of interaction between N-H bond and chlorine lone pairs; there are also effects of intramolecular hydrogen bonding and of conformation. Under acid catalysis, N-chloro-2-nitroaniline rearranges to C-chlorinated 2-nitroanilines, while with alkali it cyclizes to benzofuroxan. The acid-catalysed reaction has the same features as the Orton rearrangement of N-chloroacetanilides.