Nitrile imide–imidoylnitrene–carbodi-imide rearrangement

Gas-phase generation of benzonitrile N-methyl-imide (3) leads to rearrangement to 1-methylene-2-benzylidenehydrazine (5) and methylphenylcarbodi-imide (9); the latter is also obtained in 85% yield by flash vacuum pyrolysis of 1-methyl-5-phenyltetrazole.