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

Abstract

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. The free bases 16 and 17 display negative solvatochromism, which supports charge separated ground states similar to those of zwitterionic biscyanines, and DFT calculations at the UB3LYP/6-31G(d) level afford ΔE(ST) values of -13.6 and -18.7 kcal mol(-1), respectively that strongly favour the singlet ground state. All ring systems described are new and fully characterized.

Breathing Some New Life into an Old Topic: Chalcogen-Nitrogen π-Heterocycles as Electron Acceptors

“…1,2,5-Thiadiazole ring can be fused with triazinone 5 using tetrasulfur tetranitride as NSN transfer reagent to produce [5,6-c]thiadiazolo-7-oxo-1,3-diphenyl-1,2,4-benzotriazine 6 however in low yield [107] (Scheme 3).…”

Ring contraction of 1,3-diphenylbenzo[1,2,4]triazinyl radicals to 1,2-diphenylbenzimidazoles

“…The residue was then dissolved in DCM (5 ml), adsorbed onto silica and chromatographed. Elution with DCM removed minor non-polar side products and further elution (Et 2 O-nhexane, 1 : 1) gave the title compound 9a as colourless needles (45 mg, 95%), mp 109-110 °C (from n-hexane) (lit., 11 110-111 °C), R f (Et 2 O-n-hexane, 1 : 1) 0.32; ν max /cm −1 3063w, 3051w and 3011w (Ar CH), 1611w, 1595w, 1584w, 1526w, 1491m, 1476m, 1456m, 1445m, 1383s, 1329w, 1306w, 1279w, 1261w, 1204w, 1194w, 1182w, 1173w, 1150w, 1117w, 1109w, 1076w, 1028w, 1011w, 997w, 976w, 932w, 907w, 849w, 833w, 781m, 764s; δ H (500 MHz, CDCl 3 ) 7.89 (1H, d, J 8.0, Ar H), 7.57 (2H,d,J 7.3,Ar H),m,Ar H),24 (8H, m, Ar H); δ C (75 MHz, 151.8 (s), 142.5 (s), 137.0 (s), 136.4 (s), 130.0 (d), 129.8 (s), 129.5 (d), 129.1 (d), 128.8 (d), 128.3 (d), 127.5 (d), 123.3 (d), 122.7 (d), 119.4 (d), 110.4 (d); m/z (EI) 270 (M + , 75%), 269 (100), 166 (5), 139 (6), 135 (6), 77 (22), 63 (5), 51 (16); identical to an authentic sample.…”

“…118 °C for 20 min gave on chromatography (Et 2 O-n-hexane, 1 : 1) the title compound 9b as colourless needles (53 mg, 98%), mp (DSC) onset: 132.9 °C, peak max: 134.3 °C (from n-hexane), R f (Et 2 On-hexane, 1 : 1) 0.37 (found: C, 75.04; H, 4.22; N, 9.10. C 19 H 13 ClN 2 requires C, 74.88; H, 4.30; N, 9.19%); λ max (DCM)/ nm 233 (log ε 3.42), 302 (3.38); ν max /cm −1 3063w (Ar CH), 1611w, 1597w, 1499s, 1474m, 1460m, 1447m, 1435m, 1377m, 1331m, 1312w, 1302w, 1288w, 1273m, 1246w, 1202w, 1179w, 1157w, 1109w, 1074w, 1057m, 1028w, 988w, 978w, 937w, 922w, 854m, 841m, 824m, 812s, 775s; δ H (300 MHz, CDCl 3 ) 7.79 (1H, d, J 9.0, Ar H), m,Ar H),m,Ar H),7.23 (1H,d,J 2.1, Ar H); δ C (75 MHz, CDCl 3 ) 153.1 (s), 141.5 (s), 137.7 (s), 136.4 (s), 130.0 (d), 129.7 (d), 129.4 (s), 129.3 (d), 129.0 (s), 128.9 (d), 128.3 (d), 127.2 (d), 123.6 (d), 120.6 (d), 110.5 (d); m/z (EI) 306 (M + + 2, 32%), 304 (M + , 100), 268 (41), 166 (5), 164 (6), 152 (4), 139 (7), 135 (13), 77 (33), 63 (7), 51 (17).…”

“…3 While the Blatter radical 1a (R = H) is essentially stable in its crystalline form, it can be oxidized on treatment with either MnO 2 or KMnO 4 to the useful heterocyclic scaffold, 1,3-diphenylbenzo [e][1,2,4]triazin-7(1H)-one (3), 1d,2d which readily undergoes regiospecific addition of nucleophiles at C-6 and of electrophiles at C-8. 4 The benzotriazinone 3 also participates in a range of cyclisation reactions that led to extension of the acene core, which included the formation of new zwitterions (e.g., the quinoxalino fused 4), 5 the preparation of alkaloid-like tetraazafluoranthenones 5, 6 and π extended azole fused benzotriazinyls 6-8 1a,1b (Fig. 1).…”

Recent Developments in the Synthesis and Applications of 1,2,5-Thia- and Selenadiazoles. A Review

“…benzotriazine(86) was obtained from the corresponding oxoderivative 87 and tetrasulfur tetranitride in refluxed dimethylformamide (Scheme 41) 88. …”