反应详情

1.79 g of 6-(3-chloro-4-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone (prepared as in Preparation 8) was dissolved in 15 ml of anhydrous dimethylformamide. 0.35 g of a 55% w/w suspension of sodium hydride in mineral oil was added, and the solution was stirred for 1 hour. To this solution, was added, whilst ice-cooling, 1 ml of a dimethylformamide solution containing 1.34 g of ethyl bromoacetate, and the mixture was stirred for 1 hour at room temperature and then for 3 hours at 80° C. At the end of this time, the dimethylforamide was distilled off under reduced pressure and the mixture was diluted with water and then extracted with ethyl acetate. The extract was washed with water, dried and then evaporated to dryness. The addition of hexane precipitated 1.85 g of the title compound as white needles melting at 134°-136° C.

1. additionwas added
2. additionTo this solution, was added, whilst ice-
3. temperaturecooling
4. stirringthe mixture was stirred for 1 hour at room temperature
5. waitfor 3 hours at 80° C
6. distillationAt the end of this time, the dimethylforamide was distilled off under reduced pressure
7. additionthe mixture was diluted with water
8. extractionextracted with ethyl acetate
9. washThe extract was washed with water
10. customdried
11. customevaporated to dryness
12. additionThe addition of hexane
13. customprecipitated 1.85 g of the title compound as white needles melting at 134°-136° C.