4-Chloro-5-methoxypyridazin-3(2H)-one

932-22-9

124-41-4

63910-43-0

General procedure for the synthesis of 4-chloro-5-methoxypyridazin-3(2H)-one (10): to a solution of 4,5-dichloropyridazin-3(2H)-one (4.1 g, 24.8 mmol) in methanol (50 mL) was added sodium methanolate (2.6 g, 74.5 mmol). The reaction mixture was stirred at 80 °C overnight. Upon completion of the reaction, the mixture was concentrated under reduced pressure and purified by column chromatography [eluent: petroleum ether to petroleum ether/dichloromethane/methanol (10:1:1)] to afford the target product, 4-chloro-5-methoxypyridazin-3(2H)-one (10) (1.2 g, 30% yield), as a white solid. The procedure for the synthesis of 4-chloro-2-(2-chlorobenzyl)-5-methoxypyridazin-3(2H)-one (11) was not provided with complete information.