反应详情

A suspension of 5.18 g (0.02 mole) of 4-(3,5-dichloro-4-methylphenyl)-4-oxo-2-butenoic acid, prepared as described in Example 1(b), in 50 ml of methyl isobutyl ketone was saturated with dry hydrogen chloride gas, by blowing the gas through the suspension whilst ice-cooling and stirring it. The mixture was then stirred at room temperature for a further 1 hour, after which it was diluted with 30 ml of cold water and extracted with ethyl acetate. The extract was washed with water and then dried over anhydrous sodium sulphate, after which the solvent was distilled off and the residue was washed with a small amount of hexane and then dried, giving 5.91 g (yield 100%) of the desired 2-chloro-4-(3,5-dichloro-4-methylphenyl)-4-oxobutyric acid, melting at 129°-132° C.

1. customprepared
2. temperaturecooling
3. stirringThe mixture was then stirred at room temperature for a further 1 hour
4. extractionextracted with ethyl acetate
5. washThe extract was washed with water
6. dry with materialdried over anhydrous sodium sulphate
7. distillationafter which the solvent was distilled off
8. washthe residue was washed with a small amount of hexane
9. customdried