Novel Dimroth Rearrangements of the Benzotriazole System: 4-Amino-1-(arylsulfonyl)benzotriazoles to 4-benzotriazoles

Article abstract of DOI:10.1021/jo00027a036

A variety of mono- and diarylsulfonyl-substituted 4-aminobenzotriazoles were prepared.Thermal rearrangements of 4-amino-1-(arylsulfonyl)benzotriazoles to 4-<(arylsulfonyl)amino>benzotriazoles were observed and confirmed by separation of the rearrangement products.Their structures were characterized by spectral methods and by X-ray crystallography.The rearrangement rates were studied by variable-temperature NMR experiments.Crossover experiments support an intramolecular mechanism involving a heterolytic benzotriazole ring cleavage to form a diazo intermediate followed by recyclization to the 4-amino group.