Synthesis of 6-Bromo-4-methylbenzofuroxan

6-Bromo-4-methylbenzofuroxan (3) was prepared by the thermal decomposition of 4-bromo-2-methyl-6-nitrophenylazide in excellent yields. 1 H-NMR spectra showed that the compound (3) rapidly rearranges between the two unsymmetrical bicyclic structures. However, the methyl group and bromine may possibly function as a barrier against molecular rearrangement and so molecular rearrangement is slow enough that different chemical shifts are apparent at room temperature.