2,4-Dioxo-4-phenyl-butyric acid ethyl ester → 1-(5-Methoxy-2-pyridyl)-5-phenylpyrazole-3-carboxylic acid ethyl ester

Participants

Reaction Steps

The above-obtained 2-hydrazino-5-methoxypyridine (705 mg) and the 2,4-dioxo-4-phenylbutyric acid ethyl ester (1.12 g) prepared in Referential Example 123-1) in ethanol (25 mL) was refluxed under heat for 19 hours, and then cooled in air. The reaction solvent was removed under reduced pressure, and the residue was partitioned by use of ethyl acetate and saturated aqueous sodium hydrogencarbonate. The organic layer was washed with saturated brine, and then dried over magnesium sulfate anhydrate, followed by filtration. The solvent was removed under reduced pressure, and the residue was purified through silica gel chromatography (hexane-ethyl acetate), to thereby give 1-(5-methoxy-2-pyridyl)-5-phenylpyrazole-3-carboxylic acid ethyl ester as an amorphous product (705 mg, 43%).

Provenance & Evidence