The question of homoaromaticity in 1,6-dihydro-1,2,4,5-tetrazines

6-Methyl-N-(2-methylphenyl)-3-phenyl-1,6-dihydro-1,2,4,5-tetrazine-1-carboxamide

“…Dihydro-1,2,4,5-tetrazine has four isomers, namely 1,2-, 1,4-, 1,6-, and 3,6-dihydro-1,2,4,5-tetrazines. The 1,6-dihydro structures (Stam et al, 1982;Jennison et al, 1986) were found, by X-ray diffraction, to be homoaromatic. In continuation of our work on the structure-activity relationship of 1,6-dihydro-1,2,4,5-tetrazine derivatives (Hu et al, 2004(Hu et al, , 2005, we report the crystal structure of the title compound (I) (Fig.…”

“…For related literature, see: Hu et al (2004Hu et al ( , 2005; Jennison et al (1986); Sauer (1996); Stam et al (1982); Xu et al (2006).…”

Crystal structure of N‐(2‐methoxyphenyl)‐3,6‐diphenyl‐1,4‐dihydro‐1,2,4,5‐tetrazine‐1‐carbonamide

“…Dihydro-1,2,4,5-tetrazine has four isomers, namely 1,2-, 1,4-, 1,6-and 3,6-dihydro-1,2,4,5-tetrazine. The homoaromatic structures were proven by X-ray diffraction in the 1,6-dihydro structures [2]. There still seems to be much confusion whether 1,4-dihydro structures have homoaromaticity.…”

Synthesis and Structure Analysis of 1-(3-Methoxybenzoyl)-3,6-Diphenyl-1,4-Dihydro-1,2,4,5-Tetrazine

“…Homoaromatic structures have been demonstrated by X-ray diffraction in the 1,6-dihydro structures. 7 There seems to be some doubt as to whether the 1,4-dihydro structures have homoaromaticity. For example, X-ray diffraction reportedly showed 3,6-bis(4-chlorobenzyl)-1,4-dihydro-1,2,4,5-tetrazine to have an obvious chair conformation without a homoaromatic structure, 8 but 1,3,4,6-tetramethyl-1,4-dihydro-1,2,4,5-tetrazine was analysed by X-ray diffraction and a possible homoaromatic structure was identified.…”