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The novel heterocyclic system 10 with the phenanthrene type skeleton, in wh
ich the benzene ring is annulated with two 1,2,3,4 tetrazine 1,3 di-N-oxide
rings, is of considerable interest in the context of the high nitrogen sys
tem stability and from a heteroaromaticity standpoint. The step by step syn
thetic approach to this system involves treatment of 5 with N2O5, resulting
in the first 1,2,3,4 tetrazine 1,3 dioxide ring formation, The following d
isplacement of the chlorine atom at the 6-position with ammonia and subsequ
ent repeated treatment with N2O5 results in the second 1,2,3,4 tetrazine 1,
3 dioxide ring formation. The structure of 10 was confirmed by a C-13 and N
-14 NMR Study.