5-Chloro-1,3-dimethylpyrazole-4-carboxaldehyde → (5-chloro-1,3-dimethyl-1H-pyrazol-4-yl)methanol

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Reaction Steps

To a solution of sodium borohydride (358 mg, 9.5 mmol) in methanol (15 mL) was added a solution of 5-chloro-1,3-dimethyl-1H-pyrazole-4-carbaldehyde (1.0 g, 6.3 mmol) in methanol (5 mL) at 0° C. The mixture was stirred overnight at room temperature. The solvent was evaporated, water was added, and the mixture was extracted 3 times with ethyl acetate. The combined organic phase was washed with brine and dried over sodium sulfate. After evaporation of the solvent, (5-chloro-1,3-dimethyl-1H-pyrazol-4-yl)methanol was obtained as a white solid (690 mg, 68% yield) and used in the next step without further purification; 1H NMR (400 MHz, CDCl3): δ 1.53 (t, J=5.5 Hz, 1H), 2.28 (s, 3H), 3.77 (s, 3H), 4.49 (d, J=5.5 Hz, 2H).

Provenance & Evidence