5-氯-6-苯基-2H-哒嗪-3-酮的合成

Synthesis of 5-Chloro-6-phenyl-2H-pyridazin-3-one

6-苯基-2H-哒嗪-3-酮(2)经三氯化磷/氯气氯代制得3,5-二氯-6-苯基哒嗪,经氢氧化钠皂化,再用盐酸调至pH 8.5得到5-氯-6-苯基-2H-哒嗪-3-酮,总收率约24%(以2计)。副产物3-氯-5-羟基-6-苯基哒嗪可作为氯代反应的原料回收使用。

5-Chloro-6-phenyl-2H-pyridazin-3-one was synthesized from 6-phenyl-2H-pyridazin-3-one （2） by chlorination with phosphorus trichloride and chlorine to give 3,5-dichloro-6-phenylpyridazine, which was saponified with sodium hydroxide, followed by acidification with hydrochloric acid to pH 8.5 with an overall yield of about 24% （based on compound 2）. The by-product 3-chloro-5-hydroxy-6-phenylpyridazine from saponification can be reused as raw material in chlorination.