Novel rearrangements occurring during the thermolysis of 2,3-diphenyl-2H-azirine

G.l.c. treatment of 2,3-diphenyl-2H-azirine at 220° yields 2-phenylindole: heating 2,3-diphenyl-2H-azirine at 250° in a sealed tube produces 2-phenylindole, 2,4,5-triphenylimidazole, 1-benzyl-2,4,5-triphenylimidazole, and 2,3,4,5-tetraphenylpyrrole as major products.