Synthesis of 1,2,3,4‐Tetrazine 1,3‐Dioxides Annulated with 1,3 a,4,6 a‐Tetraazapentalene Systems

Abstract

Abstract A synthetic approach to 5,11‐dehydro‐5H,11H‐[1,2,3,4]tetrazino[5′,6′:4,5][1,2,3]triazolo[2,1‐a][1,2,3]benzotriazole 1,3‐dioxide ( 5 ) and 5,11‐dehydro‐5H,11H‐[1,2,3,4]tetrazino‐[5′,6′:4,5][1,2,3]triazolo[2,1‐a][1,2,3]benzotriazole 2,4‐dioxide ( 6 ) was developed. These ring systems are the first in which a 1,2,3,4‐tetrazine 1,3‐dioxide ring is directly fused with 1,3a,4,6a‐tetraazapentalene moiety. The synthesis started from ( tert ‐butyl‐ NNO ‐azoxy)acetonitrile ( 7 ) and involved the closure of the 1,2,3,4‐tetrazine 1,3‐dioxide ring first and then formation of the tetraazapentalene ring. The derivatives of ring systems 5 and 6 nitrated at the benzene ring were also obtained. The structures of the compounds synthesized have been confirmed by NMR spectroscopy and X‐ray diffraction studies.