Treatment of 3-amino-4-(tert-butyl)azoxyfurazan with NO2BF4 in MeCN gi
ves [1,2,5]oxadiazolo[3,4-e][1,2,3,4]tetrazine 4,6-di-N-oxide 2; N-15
labelling experiments allowed the spectra of 2 to be fully assigned an
d provided support for the proposed structure. Diazonium oxide cation
is proposed as the intermediate in ring closure.