(4+2)-cycloadditionen der 1.2.4-Triazine - ein neuer weg zu 4-H-Azepinen

1,2,4-Triazines Are Versatile Bioorthogonal Reagents

“…[21][22][23] These motifs also react efficiently with electron-rich alkenes in IED-DA reactions. [24][25][26][27][28][29] Boger further showed that 1,2,3-triazines react with electron-rich dienophiles. 30 To compare the intrinsic DA reactivities of 1,2,3-and 1,2,4-triazines with that of 1,2,4,5-tetrazine, we evaluated the activation free energies for their reactions with ethylene by density functional theory (DFT) calculations ( Figure 1A, Table S1).…”

Six‐Membered Heterocycles: Triazines, Tetrazines and Other Polyaza Systems

“…Some reviews on inter-and intramolecular Diels-Alder reactions have appeared [30,120,360,361]. 1,2,4-Triazines participate as electron-poor dienes in inverse type Diels-Alder reactions with electron-rich dienophiles such as dienes [120,244], enamines [362][363][364][365][366][367][368][369][370][371][372] or methoxyethylene [373] to yield pyridine derivatives 213 (Scheme 20.64). Cycloaddition of 1,2,4-triazines with ynamines to yield pyrimidines 214 [374][375][376] has also been studied.…”

Application of 1-Vinylimidazole in Diels-Alder Reaction of 5,5′-bi-1,2,4-Triazines

“…There has been a very limited study on the Diels-Alder reaction of vinyl acetate or methyl vinyl ether with trimethyl 1,2,4-triazine-3,5,6-tricarboxylate leading to the corresponding trimethyl pyridine-2,3,6-tricarboxylate. 9 However, somewhat similar reactions of 1,2,4-triazines with bicyclo[2.2.1]hepta-2,5-diene 9, which can be considered as an acetylene equivalent, have been extensively exploited and well documented. [9][10][11][12] We initially attempted the [4+2] cycloaddition of 1 with this dienophile, but in addition to the desired 7, the mixture was obtained containing, as its major component compound 10.…”