To a solution of ethyl 2,4-dioxo-4-phenylbutyrate (1.0 g, 4.5 mmol), methylhydrazine sulfate (1.0 g, 6.8 mmol) and sodium hydroxide (0.5 g, 13.6 mmol) in ethanol (50 mL) was added the reaction mixture. The reaction mixture was stirred at 70 °C overnight. After completion of the reaction, the reaction was quenched with ice water (100 mL), extracted with ethyl acetate, the organic phase was washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated to give the crude product. The crude product was purified by silica gel column chromatography eluting with appropriate eluent to give ethyl 1-methyl-3-phenyl-1H-pyrazole-5-carboxylate (247.5 mg, 23.9%). Mass spectrum (ESI) m/z: 231.1 [M + 1].
