Tetrahydrofuran → 1-(3,5-dichloropyridin-2-yl)-3-methyl-1H-pyrazole-5-carboxylic acid

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Reaction Steps

To a 100 mL flask, methyl 1-(3,5-dichloropyridin-2-yl)-3-methyl-1H-pyrazole-5-carboxylate (1.00 g, 3.49 mmol), tetrahydrofuran (10 mL), water (10 mL) and sodium hydroxide (0.14 g, 3.49 mmol) were added sequentially. After being stirred for 40 minutes at room temperature, all of the starting materials had disappeared. Then water (50 mL) was added. The mixture was extracted with ethyl acetate (30 mL) and the aqueous layer was acidified with concentrated hydrochloric acid to pH of 2˜3, and extracted with ethyl acetate (3×80 mL), the organic layer was washed with saturated brine (100 mL), dried over anhydrous magnesium sulfate and concentrated by rotary evaporator to give the product (0.91 g) as a white solid in 96% yield. Melting point: 227-228° C.

Provenance & Evidence