Some cyclization reactions of 1,3-diphenylbenzo[e][1,2,4]triazin-7(1H)-one: preparation and computational analysis of non symmetrical zwitterionic biscyanines.

Regioselective nucleophilic addition of bisnucleophiles 1,2-benzenediamine, 2-amino-benzenethiol, and N-phenyl-1,2-benzenediamine to 1,3-diphenylbenzo[e][1,2,4]triazin-7(1H)-one (1) at C6 followed by intramolecular cyclocondensation at the C7 carbonyl afforded highly coloured tetracenes 1,3-diphenyl-1,6-dihydro-[1,2,4]triazino[5,6-b]phenazin-4-ium 4-methylbenzenesulfonate (12), 1,3-diphenyl-1H-[1,2,4]triazino[6,5-b]phenothiazine (14) and 1,3,11-triphenyl-1,6-dihydro-[1,2,4]triazino[5,6-b]phenazin-11-ium 4-methylbenzenesulfonate (15), respectively. Neutralization of the latter with alkali gave the free base 1,3,11-triphenyl-1H-[1,2,4]triazino[5,6-b]phenazin-11-ium-6-ide (16). Furthermore, the benzotriazinone 1 reacts with dimethyl malonate to give 6-(methoxycarbonyl)-7-oxo-1,3-diphenyl-7H-benzofuro[5,6-e][1,2,4]triazin-1-ium-4-ide (17) in 74% yield, while with S(4)N(4) [5,6-c]-thiadiazolo-7-oxo-1,3-diphenyl-1,2,4-benzotriazine (22) was formed in 15% yield.

1,3-Diphenylbenzo[e][1,2,4]triazin-7(1H)-one: selected chemistry at the C-6, C-7 and C-8 positions.

1,3-Diphenylbenzo[e][1,2,4]triazin-7(1H)-one (6) reacts with tetracyanoethylene (TCNE) or tetracyanoethylene oxide (TCNEO) to give the deep green 2-[1,3-diphenylbenzo[e][1,2,4]triazin-7(1H)-ylidene]propanedinitrile (11) in 17 and 15% yields, respectively. Nucleophiles such as amines, alkoxides, thiols and Grignard reagents all reacted with the 1,3-diphenylbenzotriazinone 6 regioselectively at C-6, while halogenating agents reacted exclusively at C-8. Furthermore, 8-iodo-1,3-diphenylbenzo[e][1,2,4]triazin-7(1H)-one (32) undergoes palladium-catalysed Suzuki-Miyaura and Stille coupling reactions to give 8-aryl- or heteroaryl-substituted benzotriazinones.

Characterization and magnetic properties of a "super stable" radical 1,3-diphenyl-7-trifluoromethyl-1,4-dihydro-1,2,4-benzotriazin-4-yl.

1,3-Diphenyl-7-trifluoromethyl-1,4-dihydro-1,2,4-benzotriazin-4-yl (4), prepared in high yield via the catalytic oxidation of the corresponding amidrazone 5 by using Pd/C (1.6 mol %) and 1,8-diazabicyclo[5.4.