ISOMERIC SYDNONES: I. THE REACTIONS OF 1- AND 2-BENZOYL-1-METHYLHYDRAZINES AND PHOSGENE

The oxygen–carbonyl isomeric sydnone (V) has been synthesized from 1-benzoyl-1-methyl-hydrazine hydrochloride (VII) and phosgene. The isosydnone V itself reacts with phosgene to form 2-chloro-5-phenyl-1,3,4-oxadiazole (VI), a new substituted 1,3,4-oxadiazole. Thermal rearrangement of the salt VII takes place at 200° to give 1-benzoyl-2-methylhydrazine, which with phosgene forms the isomer XI. Some mechanistic pathways for these transformations are discussed.