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
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
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 in the area of energetic chemistry.
The compound 3,6-di-2-pyridyl-1,2,4,5-tetrazine'[3] has two pyridine substituents and is of importance as a reagent in Diels-Alder reactions. It reacts with norbornadiene in a sequence of one DA reaction and two retro-DA reactions to cyclopentadiene and a pyridazine with exchange of an acetylene unit:[4]
With norbornadiene fused to an arene the reaction stops at an intermediary stage [5]
See also
- 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
- ^ Alvarez-Builla, Julio; Jose Vaquero, Juan; Barluenga, José (2011). Modern Heterocyclic Chemistry. Wiley-VCH. p. 1778. ISBN 978-3527332014.
- ^ (see United States Patent 6645325)
- ^ Datasheet: Link
- ^ 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