反应详情

温度

60 °C

10.2 g (0.1 mole) of acetic anhydride were added to 9.3 g (0.1 mole) of glyoxylic acid monohydrate and the mixture was heated, with stirring, on an oil bath at 60° C. for 10 minutes to obtain a homogeneous solution. To this solution were added, in turn, 20.3 g (0.1 mole) of 3,5-dichloro-4-methylacetophenone, prepared as described in step (a) above, 28.8 g of acetic acid and a catalytic amount (300 mg) of concentrated sulphuric acid, whilst ice-cooling. The mixture was then heated, with stirring, on an oil bath at 105°-110° C. for 2 hours, after which it was cooled and 100 ml of diisopropyl ether were added. The mixture was stirred and the resulting crystals were collected by filtration and washed first with water and then with a small amount of diisopropyl ether, after which they were dried to give 20.8 g (yield 80.3%) of the desired 4-(3,5-dichloro-4-methylphenyl)-4-oxo-2-butenoic acid, melting at 206°-216° C.

1. temperaturethe mixture was heated
2. customto obtain a homogeneous solution
3. customprepared
4. temperatureThe mixture was then heated
5. stirringwith stirring, on an oil bath at 105°-110° C. for 2 hours
6. temperatureafter which it was cooled
7. stirringThe mixture was stirred
8. filtrationthe resulting crystals were collected by filtration
9. washwashed first with water
10. dry with materialwith a small amount of diisopropyl ether, after which they were dried