反应详情

A mixture of 5-amino-4-cyano-1-(2,3,4-trichlorophenyl)pyrazole (10 g) and p-toluenesulphonic acid hydrate (0.1 g) in triethylorthoformate (40 ml) was heated at reflux for 1 hour. After cooling, the reaction mixture was evaporated to dryness. The residue was dissolved in dichloromethane and saturated aqueous sodium bicarbonate solution was added. The organic phase was removed, dried over anhydrous magnesium sulphate and evaporated to give a colourless solid which was recrystallised from a mixture of ethyl acetate and hexane to give 4-cyano-5-ethoxymethyleneamino-1-(2,3,4-trichlorophenyl)pyrazole (11.0 g), m.p. 131°-132° C., in the form of colourless crystals.

1. temperaturewas heated
2. temperatureat reflux for 1 hour
3. temperatureAfter cooling
4. customthe reaction mixture was evaporated to dryness
5. dissolutionThe residue was dissolved in dichloromethane
6. additionsaturated aqueous sodium bicarbonate solution was added
7. customThe organic phase was removed
8. dry with materialdried over anhydrous magnesium sulphate
9. customevaporated
10. customto give a colourless solid which
11. customwas recrystallised from a mixture of ethyl acetate and hexane