The 1,2,3‐Triazines

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

“…However, when 3,6-diaryl-1,2,4,5-tetrazines and C 60 react upon irradiation with visible light, the four membered ring-containing C 62 derivatives were obtained [805]. 20.5.5.3 Reactions with Oxidizing Reagents 1,4-Dihydrotetrazines have been aromatized to tetrazines by exposure to nitrous gases [784]. 1,2,4,5-Tetrazines have been oxidized by DBU to obtain a novel azepine derivative [806].…”

“…20.4.5.7 Reactions of Metallated 1,3,5-Triazines Metallated triazines react with electrophiles to give different substituted derivatives. Chloro-1,3,5-triazines are lithiated using lithium powder and naphthalene in the presence of various electrophiles such as aldehydes and ketones to give, after hydrolysis, the expected substituted triazines.…”

“…Several reviews on the chemistry of 1,2,3-triazine, also called n-triazine, have been published [12,[20][21][22][23][24][25][26]. Study of the reactivity and stability of the unsubstituted ring systems has been possible only since 1981 when the first synthesis of the parent compound 1 was reported [27].…”

Antitumour imidazotetrazines. Synthesis and chemistry of 4-oxo-3,4-dihydroimidazo[5,1-d][1,2,3,5]tetrazine-8-carboxamide (nor-temozolomide): an intermediate for the preparation of the antitumour drug temozolomide and analogues, avoiding the use of isocyanates

“…It would be interesting, for example, to compare the properties of 1b and the related bicyclic compound 1,2,3-benzotriazin-4(3H)-one on which there is a voluminous literature. 17 In the case of 9 where the nitrogen atom bearing the hydroxymethyl fragment is flanked with two EWGs (azo and carbonyl), past experience would predict that this compound would be stable under ambient conditions. 18 In fact, elimination of formaldehyde from 9 to afford 1b occurred only slowly in DMSO at room temperature.…”

“…In this respect the presumed ambident anion 14 behaved like the corresponding anion generated from 1,2,3-benzotriazin-4(3H)-one. 17 Changing the base from NaH to DBU (in MeCN) or K 2 CO 3 (in DMF) had little influence on reaction outcome. Interestingly, performing the reaction at À20 C increased the ratio of 1a to 14; only traces of 14 (<1%) were apparent from the NMR spectrum of the reaction mixture.…”