Triethylamine → 1-(6-Methoxy-3-pyridyl)-5-(3-methylphenyl)pyrazole-3-carboxylic acid ethyl ester

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Reaction Steps

5-Hydrazino-2-methoxypyridine hydrochloride (0.380 g) obtained from Referential Example 1 and triethylamine (0.30 mL) were added to a solution of the above-obtained 4-(3-methylphenyl)-2,4-dioxobutanoic acid ethyl ester (1.014 g) dissolved in ethanol (20 mL) at room temperature. The resultant mixture was refluxed under heat for 14 hours, and then cooled in air. The solvent was evaporated under reduced pressure, and the residue was partitioned between chloroform and water. The aqueous layer was extracted with chloroform. The organic layer was washed with saturated brine and dried over sodium sulfate anhydrate, followed by filtration. The solvent was evaporated under reduced pressure, and the residue was subjected to silica gel column chromatography (hexane-ethyl acetate: 20%), to thereby give the title compound as an oily substance (0.451 g, 62%).

Provenance & Evidence