Synthesis of Functional Derivatives of Benzodifurazan

Benzodifurazan reacts with 1,3-dibromo-5,5-dimethylhydantoin in sulfuric acid to form 5-bromo-4,5-dihydrobenzo[1,2-c:3,4-c']bis([1,2,5]oxadiazol)-4-ol (A). The structure of the product was established by X-ray diffraction analysis. It was found that compound A exhibits properties of epoxides: it readily takes up nucleophiles to form alcohols, whose reaction with p-toluenesulfonyl chloride in the presence of tetrabutylammonium bromide and sodium hydroxide in benzene gives functional derivatives of benzodifurazan. On treatment with a base [Ca(OH)₂], compound A converts to 1a,7b-dihydrooxireno[2',3':5,6]benzo[1,2-c:3,4-c']bis([1,2,5]oxadiazole).