反应详情

25.0 g of 3,4-difluoroaniline are dissolved in 120 of 2-butanol. 50 ml of a saturated solution of hydrogen chloride in 2-butanol are added slowly and afterwards 47.6 g (0.1936 mol) of p-chloranil are also added. With a good stirring and at reflux temperature (100-110° C.) a solution of 19.4 ml (0.236 mol) of crotonaldehyde in 45 ml of butan-2-ol is dropped slowly (ca. 2 hr). The whole is refluxed for two additional hours and then evaporated to dryness. The residue is taken with excess THF and is filtered and washed thoroughly with THF until the filtering appears to be uncoloured. The solid thus obtained is solved in water, filtered from some solid impurities and washed with ethyl ether. The aqueous layer is made slightly alkaline with 2N NaOH solution and then extracted with diethyl ether. The ethereal layer is dried and treated with a little decolourising charcoal. After evaporation a white solid is obtained (22.7 g, 65%).

1. additionis dropped slowly (ca. 2 hr)
2. temperatureThe whole is refluxed for two additional hours
3. customevaporated to dryness
4. filtrationis filtered
5. washwashed thoroughly with THF until the filtering
6. customThe solid thus obtained
7. filtrationfiltered from some solid impurities
8. washwashed with ethyl ether
9. extractionextracted with diethyl ether
10. customThe ethereal layer is dried
11. additiontreated with a little decolourising charcoal
12. customAfter evaporation a white solid
13. customis obtained (22.7 g, 65%)