Bromide ion → 4-(1-(4-(trifluoromethoxy)phenyl)-1H-1,2,4-triazol-3-yl)aniline

Participants

Reaction Conditions

Reaction Steps

1-(4-Trifluoromethoxyphenyl)-3-(4-nitrophenyl)-1H-[1,2,4]triazole. A solution of NBS (0.70 g, 3.9 mmol) in CH2Cl2 (25 mL) was stirred under nitrogen at 0° C. while dimethyl sulfide (0.40 g, 6.5 mmol) was added via syringe. The solution, which forms a white solid, was then cooled to −20° C., and N-(4-nitrobenzylidene)-N′-(4-trifluoromethoxyphenyl)-hydrazine (0.70 g, 2.15 mmol) in CH2Cl2 (10 mL) was added. The solution was allowed to warm to ambient temperature and stirred an additional 2 h. The resulting orange solution was then diluted with CH2Cl2 (25 mL) and washed with water and brine before drying and concentrating. The resulting orange solid hydrazonyl bromide (0.9 g) was then treated directly with tetrazole (154 mg, 2.2 mmol) and triethylamine (280 μL, 0.23 mmol) in absolute EtOH (5 mL). The resulting orange-brown solution was heated at reflux for 2 h. TLC showed that the initial bromide was first converted into two yellow intermediates, which were replaced by a single, colorless spot. The orange solution was then concentrated and purified by chromatography (2:1:2 hexanes/EtOAc/CH2Cl2), yielding the title compound (0.30 g) as a light yellow solid: mp 147° C.; 1H NMR (300 MHz, CDCl3) 8.68 (s, 1H), 8.40 (d, J=5 Hz, 2H), 8.35 (d, J=5 Hz, 2H), 7.85 (d, J=8 Hz, 2H), 7.42 (d, J=8 Hz, 2H); EIMS m/z 350 (M+, 100), 299 (57).

Provenance & Evidence