Potassium Carbonate → 4-Chloro-5-methoxy-2-phenyl-3(2H)-pyridazinone

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Reaction Steps

The title compound was prepared according to the method of (S. Cho et al. described in J. Het. Chem., (1996), 33, 1579-1582), starting with the N-phenyl-dichloropyridazinone. A mixture of 2-phenyl-4,5-dichloro-3(2H)-pyridazinone (1 g, 4.1 mmol) and finely powdered, anhydrous K2CO3 (580 mg, 4.2 mmol) in 50 mL of methanol was heated at reflux for 5 hours and concentrated in vacuo. The residue was partitioned between water and ethyl acetate. The acetate layer was washed with water, and brine to provide 2-phenyl-4-chloro-5-methoxy-3(2H)-pyridazinone (yield: 920 mg, 95%). 1H NMR (300 MHz, DMSO-d6) δ 4.15 (s, 3H), 7.50 (m, 5H), 8.43 (s, 1H). MS (DCI/NH3) m/z 237 (M+H)+, 254 (M+NH4)+.

Provenance & Evidence