反应详情

4.4 g of ethyl 1-phenylpyrazole-5-carboxylate from Example 1 were stirred for 6 hours at room temperature with 10 ml of 16.5% strength aqueous NaOH and 10 ml of ethanol; the ethanol was removed by distillation, the aqueous phase was extracted twice with 10 ml of toluene, and the pH was adjusted to 3 using concentrated HCl. The precipitate was filtered off under suction, washed with a little water and dried: 3.1 g of product of boiling point 182°-183° C. were obtained.

1. customthe ethanol was removed by distillation
2. extractionthe aqueous phase was extracted twice with 10 ml of toluene
3. filtrationThe precipitate was filtered off under suction
4. washwashed with a little water
5. customdried