反应详情

3-(4'-Chlorophenyl)-4-hydroxy-6-bromopyridazine 3-(4'-Chlorophenyl)-4,6-dibromopyridazine (52.2 g, 0.1498 mol) was dissolved in hot dioxane (300 ml) and a solution of 12 g (0.3 mol) of sodium hydroxide solution in 50 ml of water was added dropwise in the course of 10 minutes while the mixture was refluxed gently. The mixture was maintained under reflux for a further 4.5 hours, the dioxane was evaporated in vacuo, and the solid residue was dissolved in 1 l of hot water (95° C.). A small amount of solid product (tarry) was filtered under hot conditions with the aid of animal charcoal, and the hydrolysis product was precipitated using hydrochloric acid. The product which had been isolated (solid) by filtering off with suction was, while still moist, suspended in 1 l of water, after which process the pH of the suspension, at 65° C., was brought to 9-10 using ammonia. Most of the product dissolved, and the insoluble components were isolated and again treated with ammonia. The combined filtrates were then acidified using hydrochloric acid, and the 3-(4'-chlorophenyl)-4-hydroxy-6-bromopyridazine which was obtained was isolated, washed with water and dried to constant weight. 27.5 g, 0.09631 mol, 64.3% of theory, m.p.=262°-264° C. was thereby obtained.

1. temperaturewas refluxed gently
2. temperatureThe mixture was maintained
3. temperatureunder reflux for a further 4.5 hours
4. customthe dioxane was evaporated in vacuo
5. dissolutionthe solid residue was dissolved in 1 l of hot water (95° C.)
6. filtrationA small amount of solid product (tarry) was filtered under hot conditions with the aid of animal charcoal
7. customthe hydrolysis product was precipitated
8. customThe product which had been isolated (solid)
9. filtrationby filtering off with suction
10. customat 65° C.
11. dissolutionMost of the product dissolved
12. customthe insoluble components were isolated