Boron tribromide → 5-(4-methyl-5-(2-(trifluoromethyl)pyridin-3-yl)-4H-1,2,4-triazol-3-yl)-3-nitrobenzene-1,2-diol

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Reaction Steps

To a stirred suspension of 3-(5-(3,4-dimethoxy-5-nitrophenyl)-4-methyl-4H-1,2,4-triazol-3-yl)-2-(trifluoromethyl)pyridine (0.192 g, 0.47 mmol) in dichloromethane (20 mL) at −78° C. under argon was added boron tribromide (0.47 g, 1.88 mmol) dropwise. The resulting purple suspension was then allowed to stir at room temperature for seven hours before being cooled in an ice-water bath. The mixture was carefully quenched by the addition of methanol. After stirring at room temperature for thirty minutes, the volatiles were evaporated and the residue stirred with 2 N hydrochloric acid (5 mL) for thirty minutes. The resulting solid was filtered off, washed with water (25 mL) and then cold isopropanol (5 mL) to give, after drying, 5-(4-methyl-5-(2-(trifluoromethyl)pyridin-3-yl)-4H-1,2,4-triazol-3-yl)-3-nitrobenzene-1,2-diol was obtained as an orange solid, 0.154 g (86%).

Provenance & Evidence