The reaction of 19.6 g (162.95 mmol) acetophenone and 5 g (54.32 mmol) oxaloacetic acid monohydrate was stirred at 100 °C for 2 hours. Upon completion of the reaction, the reaction solution was cooled to 40 °C, followed by the addition of 20 mL of water and 4 mL of ammonia. The mixture was extracted twice with 50 mL of dichloromethane. To the resulting aqueous phase, 2.64 mL (53.32 mmol) of hydrazine monohydrate was added, and the reaction was continued with stirring of the mixture at 100 °C for 2 hours. At the end of the reaction, the reaction solution was cooled to room temperature. The precipitated crystals were collected by filtration, washed with water and dried in a vacuum oven at 50 °C overnight. Finally, 4.3 g (24.97 mmol, 15% yield) of 6-phenyl-3-pyridazinone was obtained as colorless crystals.LC-MS (Method 7): Rt = 1.39 min; m/z = 173 (M + H)+. 1H-NMR (400 MHz, DMSO-d6, δ/ppm): 13.2 (s, 1H), 8.04 (d, 1H), 7.86 (d, 2H), 7.53-7.41 (m, 3H), 7.00 (d, 1H).
