1,2,4,5-Tetrazine, hexahydro-1,4-diphenyl

The only report in the literature of the preparation of a tetrazine from a thiourea is that of Naik,270 who claimed to have isolated hexahydro-l,2,4,5-tetraphenyl-l,2,4,5-tetrazine-3,6-dithione (133) on treatment of l,3-diphenyl-2-thiourea with sulfur monochloride in refluxing benzene. Since the only evidence presented for structure 133... 

Thermolysis of 3,6-diphenyl-l,4-di(phenylsulfonyl)-l,4-dihydro-l,2,4,5-tetrazine (127) in boiling toluene gives benzenesulfonic anhydride (128), phenyl benzenethiosulfonate (129), small amounts of diphenyl disulfide (130), 3,6-diphenyl-l,2,4,5-tetrazine (51) and a rearrangement product, 3,6-diphenyl-l,2-di(phenylsulfonyl)-l,2-dihydro-l,2,4,5-tetrazine (79) (79BCJ483). 3,6-Disubstituted hexahydro-1,2,4,5-tetrazines (132) afforded aldehyde hydrazones (133) when heated at their melting point (63AG1204). 

No photolyses of hexahydro-1,2,4,5-tetrazines have been published. The kinetics of the photodecomposition of 1,3,5-triphenylverdazyl (61) was studied by Soviet authors in various hydrocarbons. The rate depends on the solvent. The excited radical is consumed by H extraction from the solvent and by dissociation at the N—N bond, forming the product 1,3-diphenyl-l,2,4-triazole (138), which catalyzes the decomposition of the verdazyl radical (74IZV2204). The dipole moment of (61) in the excited state is 9 1 D in the ground state it is 2.94 D. 

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See also in sourсe #XX -- [ ]

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