反应详情

An 86.3 g sample of 6-(p-bromophenyl)-4,5-dihydro-3-(2H)-pyridazinone (prepared as in U.S. Pat. No. 3,689,652 Example 5) is dissolved in 500 ml. of glacial acetic acid by heating to 80° C. with continuous stirring. A solution of 60 g. of bromine in 80 ml. of acetic acid is added dropwise at 75°-80° C over a 1 hour period. A solid is separated near the end of the addition. The reaction mixture is heated with stirring on the steam bath for half an hour mote, then is poured into 3 liters of cracked ice-water. The white solid formed is collected by filtration and is air dried. The product is then recrystallized from ethyl alcohol to afford 6-(p-bromophenyl)-3(2H)-pyridazinone.

1. dissolution3,689,652 Example 5) is dissolved in 500 ml
2. customA solid is separated near the end of the addition
3. temperatureThe reaction mixture is heated
4. additionis poured into 3 liters of cracked ice-water
5. customThe white solid formed
6. filtrationis collected by filtration
7. customdried
8. customThe product is then recrystallized from ethyl alcohol