反应详情

21.2 g of benzaldehyde is added to a suspension of 25 g of 3-amino-4-ethoxycarbonylpyrazole in 200 ml of toluene. The whole is boiled while separating water. In 3 hours a total of 5 ml of water collects. After the toluene has been evaporated, 50 ml of methanol and 50 ml of THF are added and, under cooling, 23 g of NaBH4 is added at 0°-5° C. After 4 hours' at room temperature, the solvent mixture is drawn off; then 200 ml of ice water is added the whole is extracted three times with 150 ml of methylene chloride each time and the extract is dried over Na2SO4. After concentration, an oil remains that is recrystallized from ligroin/toluene; m.p. 99°-100° C.

1. customwhile separating water
2. customAfter the toluene has been evaporated
3. addition50 ml of methanol and 50 ml of THF are added
4. temperatureunder cooling
5. addition23 g of NaBH4 is added at 0°-5° C
6. waitAfter 4 hours' at room temperature
7. additionthen 200 ml of ice water is added the whole
8. extractionis extracted three times with 150 ml of methylene chloride each time
9. dry with materialthe extract is dried over Na2SO4
10. concentrationAfter concentration
11. customthat is recrystallized from ligroin/toluene