Sodium Hydroxide → N-Methyl-3,5-difluoromethyl-4 pyrazolecarboxylic acid

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Reaction Steps

N-Methyl-3,5-difluoromethyl-4-pyrazolecarboxylic acid ethyl ester (0.5 g, 2.0 mmol) in ethanol (3 ml) was admixed gradually with an 8N aqueous sodium hydroxide solution (0.8 ml) and stirred at room temperature for 2 h. The solvent was removed by rotary evaporation; the residue was taken up in water (10 ml) and extracted with diethyl ether (10 ml). Acidification to pH 1 with 6M HCl was followed by extraction with ethyl acetate (3×10 ml). The combined organic phases were dried over sodium sulphate and filtered, and the solvent was removed by rotary evaporation. N-Methyl-3,5-difluoromethyl-4-pyrazolecarboxylic acid (0.44 g, 1.95 mmol, 97%) was isolated as a colourless solid.

Provenance & Evidence