2-Alkyl-1,2,3,4-benzotetrazinium Salts: Synthesis and NMR Studies of the Novel 2-Alkyl-1,2,3,4-tetrazinium/ortho-(Alkylazo)diazonium Equilibrium

Synthesis of 2-alkyl-1,2,4-benzotriazin-3(2h)-ones and 2-alkyl-1,4-dihydro-1,2,4-benzotriazin-3(2h)-ones

“…Azoanilines 1a,b and 2 (alkyl azo)benzodiazonium tetrafluoroborates 2a-f,h were prepared as described earlier. 8 2,3,4 Tribromo 6 (tert butylazo)aniline (1g). A solution of 1 (2 amino 3,4,5 tribromophenyl) 2 (tert butyl)diazene 1 oxide (1.24 g, 2.9 mmol) in anhydrous ether (10 mL) was added at -15 °C to a stirred suspension of LiAlH 4 (220 mg, 5.8 mmol) in anhydrous ether (10 mL).…”

“…8 It is worth noting that in partially reduced com pounds 4, the signal for the Bu t group is shifted to a considerably higher field (δ 1.12-1.14) compared to the corresponding signal in compound 3. Such a difference can be associated with the greater contributions from reso nance structures 3´ and 3″ than from 4´ and 4″.…”

“…As demonstrated by us earlier, 8 2 alkylbenzotetrazi nium salts exist in solutions in equilibrium with o (alkylazo)aryldiazonium salts (Scheme 1). Diazotiza tion of the corresponding o (alkylazo)anilines 1a-h gave o (alkylazo)aryldiazonium tetrafluoroborates 2´a-h.…”

Synthesis and tautomeric transformations of 2-(tert-butyl)-1,2,4-benzotriazine-3(2H)-thiones

“…11 Diazotization of ortho (tert butylazo)anilines 1a-g with nitrosonium tetrafluoroborate gave the correspond ing ortho (tert butylazo)phenyldiazonium tetrafluoro borates 2a-g (see Ref. 12). As we have found earlier, 12 ortho (alkylazo)phenyldiazonium salts 2 exist in solutions in equilibrium with 2 alkylbenzotetrazinium salts 2´ Russ.Chem.Bull., Int.Ed., Vol.…”

“…Azoanilines 1a-g and 2 (alkylazo)benzodiazonium tetrafluoroborates 2a-g were pre pared as described earlier. 12 Synthesis of 2 (tert butyl) 1 (2 isothiocyanatophenyl)di azenes 3a,d,e and 2 (tert butyl) 1,2,4 benzotriazine 3(2H ) thiones 3´a-g by reactions of salts 2a-g/2´a-g with sodium thiocyanate (general procedure). Sodium thiocyanate (49 mg, 0.6 mmol) was added in one portion to a stirred solution of salt 2 (0.12 mmol) in anhydrous CH 3 CN (5 mL).…”