反应详情

温度

70 °C

4-(Pentafluorophenyl)-1-carbethoxysemicarbazide, 2.13 g (0.0068 M), and potassium carbonate, 0.938 g (0.0068 M), are added to 75 ml of water. The mixture is heated at 70° C. under N2 about 12 hours. The solution is cooled in an ice bath and filtered to remove a trace of starting material. The pH of the solution is adjusted to pH 7 with concentrated HCl and extracted with ethyl acetate to remove a product which is less polar than the urazole in the TLC system, chloroform/ethyl acetate/acetic acid (5/5/1). The pH of the solution is reduced to 1 or 2 with concentrated HCl and then extracted with ethyl acetate. About 1/3 of a volume of toluene is added to the ethyl acetate and the solvents evaporated. The resulting crude solid weighs 0.569 g. The product is purified by two crystallizations from ethyl acetate/toluene (1/3 by vol). The yield of purified material is 0.476 g. It is recrystallized from H2O, mp 223°-226°.

1. temperatureThe solution is cooled in an ice bath
2. filtrationfiltered
3. customto remove a trace of starting material
4. extractionextracted with ethyl acetate
5. customto remove a product which
6. extractionextracted with ethyl acetate
7. additionAbout 1/3 of a volume of toluene is added to the ethyl acetate
8. customthe solvents evaporated
9. customThe product is purified by two crystallizations from ethyl acetate/toluene (1/3 by vol)
10. customIt is recrystallized from H2O, mp 223°-226°