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0 °C

A solution of 5-methoxy-1-methyl-1H-pyrazole (0.500 g, 4.46 mmol) in MeOH (50.0 mL) was cooled to 0° C. and charged with pyridinium tribromide (1.43 g, 4.46 mmol) in portions. The solution was stirred for 1 h at 0° C. then for an additional 16 h at rt. The reaction mixture was charged with sat. NaHCO3 (2.5 mL) and diluted with H2O and extracted with CHCl3 (3×). The combined organic fractions were dried over Na2SO4, filtered and concentrated in vacuo resulting in 647 mg, 76% yield of the title compound as a red oil. This material was used in the next step without further purification. 1H NMR (400 MHz, CD3OD): δ=3.66 (s, 3H), 4.07 (s, 3H), 7.30 (s, 1H). MS (ES+): m/z 190.98, 192.99 (49.5/50.5) [MH+]. HPLC: tR=3.33 min (polar—5 min, ZQ3).

1. waitfor an additional 16 h at rt
2. extractionextracted with CHCl3 (3×)
3. dry with materialThe combined organic fractions were dried over Na2SO4
4. filtrationfiltered
5. concentrationconcentrated in vacuo