Tetrazine
Tetrazine is a compound that consists of a six-membered aromatic ring containing four nitrogen atoms with the molecular formula C2H2N4. The name tetrazine is used in the nomenclature of derivatives of this compound. Three core-ring isomers exist: 1,2,3,4-tetrazines, 1,2,3,5-tetrazines, and 1,2,4,5-tetrazines, also known as v-tetrazines, as-tetrazines and s-tetrazines respectively.[1]
1,2,3,4-Tetrazines
[edit]1,2,3,4-Tetrazines are often isolated fused to an aromatic ring system and are stabilized as the dioxide derivatives.
1,2,4,5-Tetrazine
[edit]1,2,4,5-Tetrazines are very well known and myriad 3,6-disubstituted 1,2,4,5-tetrazines are known.[2] These materials are of use[vague] in the area of energetic chemistry.[citation needed]
Heavily substituted tetrazines form the verdazyls, a family of stable radicals.[3]
Protected tetrazines are strong acetylene acceptors in Diels-Alder equilibria. For example, dipyridinyl 1,2,4,5-tetrazine abstracts acetylene from norbornadiene to cyclopentadiene and a pyridazine:[4]
With norbornadiene fused to an arene the reaction stops at an intermediary stage.[5]
See also
[edit]
- 6-membered rings with one nitrogen atom: pyridine
- 6-membered rings with two nitrogen atoms: diazines
- 6-membered rings with three nitrogen atoms: triazines
- 6-membered rings with five nitrogen atoms: pentazine
- 6-membered rings with six nitrogen atoms: hexazine
References
[edit]- ^ Alvarez-Builla, Julio; Jose Vaquero, Juan; Barluenga, José (2011). Modern Heterocyclic Chemistry. Wiley-VCH. p. 1778. ISBN 978-3527332014.
- ^ (see United States Patent 6645325)
- ^ Hicks, Robin G. (2010). "Verdazyls and related radicals containing the hydrazyl [R2N–NR] group". In Hicks, Robin G. (ed.). Stable Radicals. Wiley. pp. 246–264. ISBN 978-0-470-77083-2.
- ^
- Dalkılıç, Erdin, and Arif Daştan. "Synthesis of cyclopentadiene derivatives by retro-Diels–Alder reaction of norbornadiene derivatives." Tetrahedron 71.13 (2015): 1966-1970.
- Dalkılıç, Erdin, et al. "Novel and versatile protocol for the preparation of functionalized benzocyclotrimers." Tetrahedron Letters 50.17 (2009): 1989-1991.
- ^ π-Bond Screening in Benzonorbornadienes: The Role of 7-Substituents in Governing the Facial Selectivity for the Diels-Alder Reaction of Benzonorbornadienes with 3,6-Di(2-pyridyl)-s-Tetrazine. Ronald N. Warrener and Peter A. Harrison Molecules 2001, 6, 353–369 Online Article