Phosphorus tribromide → 5-(bromomethyl)-1-methyl-3-[4-(trifluoromethoxy)phenyl]-1H-pyrazole

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Reaction Steps

PBr3 (0.15 mL, 1.60 mmol) was added to a solution of alcohol 72 (0.205 g, 0.75 mmol) in Et2O (10 mL) at 0° C. The mixture was stirred at room temperature for 16 h, cooled to 0° C., quenched with ice and diluted with Et2O (100 mL). Chromatography of the organic portion on silica gel (eluting with CH2Cl2) gave 5-(bromomethyl)-1-methyl-3-[4-(trifluoromethoxy)phenyl]-1H-pyrazole (73) (0.212 g, 85%) as a white solid: mp 70-71° C.; 1H NMR (CDCl3) δ 7.76 (d, J=8.9 Hz, 2H), 7.22 (d, J=8.9 Hz, 2H), 6.55 (s, 1H), 4.50 (s, 2H), 3.94 (s, 3H). APCI MS m/z 335, 337 [M+H]+.

Provenance & Evidence