Ethyl 2,4-dioxovalerate → Ethyl 1-(4-methoxyphenyl)-3-methyl-1H-pyrazole-5-carboxylate

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Reaction Steps

4-Methoxyphenylhydrazine hydrochloride (6.05 g, 34.8 mmol) and ethyl 2,4-dioxovalerate (4.45 mL, 31.6 mmol) were stirred overnight at 80° C. in ethanol (80 mL). After the solution was allowed to cool to room temperature, it was diluted with water and extracted with ethyl acetate. The organic layer was washed with water, 1 N HCl, and saturated sodium bicarbonate. Concentration and SiO2 chromatography with 20-30% ethyl acetate/hexanes gave 3.1 g of the title compound along with 2.9 g of 1-(4-methoxyphenyl)-5-methyl-1H-pyrazole-3-carboxylic acid ethyl ester.

Provenance & Evidence