FORMATION OF BENZIMIDAZOLE DERIVATIVES DURING ELECTRON IONIZATION INDUCED FRAGMENTATION AND PYROLYSIS OF N-BENZYL-O-NITROANILINE

Decomposition of N-benzyl-o-nitroaniline during pyrolysis and upon ele ctron ionization has been studied. Pyrolysis of N-benzyl-o-nitroanilin e starts above 450 degrees C and yields 2-phenylbenzimidazole and 1-ph enyl-1,3-dihydrobenzimidazol-2-one as the main products. Upon electron ionization N-benzyl-o-nitroaniline undergoes several fragmentations, the most important being eliminations of H2O, OH. and HO2.. All of the se processes are the examples of different ortho-effects. Elimination of H2O leads mainly to the formation of 1-phenyl-1,3-dihydrobenzimidaz ol-2-one, similar to the pyrolytic decomposition, Reaction mechanisms for the main fragmentation processes are discussed. (C) 1998 John Wile y & Sons, Ltd.