Synthesis, Structure and Transformations of the First 1,2,3,4-Tetrazine-1-N-oxide

The first representative of the 1,2,3,4-tetrazine-N-oxides, 5,7-dibromobenzo-1,2,3,4-tetrazine-1-N-oxide 4b, has been obtained by intramolecular reaction of o-(tert-butylazoxy)phenyldiazonium tetrafluoroborate 2b. Compound 4b has been characterized by NMR spectroscopy and an X-ray diffraction study and its transformation 4b→ 5b→ 6b investigated; o-azidonitrosobenzene 5b was isolated and characterized for the first time.