反应详情

温度

40 °C

300 ml of 96% strength sulphuric acid are cautiously added to 40.0 g (201.8 mmol) of 5-amino-1-(2-methylphenyl)-1H-pyrazole-4-carbonitrile (Example 9A) while cooling in ice. The mixture is then heated to 40° C. and stirred for 2 hours at this temperature. After cooling, it is poured into 2 l of ice-water and cautiously neutralized with 50% strength sodium hydroxide solution. After extraction with ethyl acetate three times (2 l each time) the combined organic phases are washed with saturated sodium chloride solution and dried over sodium sulphate, and the solvent is distilled off under reduced pressure. 36.0 g (82% of theory) of product (purity >90%) are obtained and are employed without further purification in subsequent reactions.

1. temperaturewhile cooling in ice
2. temperatureAfter cooling
3. extractionAfter extraction with ethyl acetate three times (2 l each time) the combined organic phases
4. washare washed with saturated sodium chloride solution
5. dry with materialdried over sodium sulphate
6. distillationthe solvent is distilled off under reduced pressure
7. custom36.0 g (82% of theory) of product (purity >90%) are obtained
8. customare employed without further purification in subsequent reactions