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

Synthesis

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.

References

[1] Journal of Medicinal Chemistry, 2004, vol. 47, # 19, p. 4716 - 4730
[2] Patent: WO2015/143164, 2015, A1. Location in patent: Page/Page column 115
[3] Monatshefte fuer Chemie, 1989, vol. 120, p. 329 - 342