反应详情

57.1 g of 3-(4-chloro-2-fluorophenyl)-5-hydroxy-1-methyl-1H-pyrazole from Example 2.1 were initially charged in 500 ml of dioxane. A solution of 18.8 g of NaOH in 50 ml of H2O was added, the mixture was heated at reflux and 85 g (0.98 mol=3.9 eq.) of gaseous chlorodifluoromethane were introduced. The mixture was poured into 1.5 l of water and extracted twice with 500 ml of MTBE, and the combined organic phases were extracted once with 500 ml of water and once with 500 ml of saturated sodium chloride solution. Drying and concentration of the organic phase gave 57.6 g of 53% pure 3-(4-chloro-2-fluorophenyl)-5-difluoromethoxy-1-methyl-1H-pyrazole as an oil which was purified further by vacuum distillation. This gave the title compound in a purity of 94% in a yield of 43.8%.

1. temperaturethe mixture was heated
2. temperatureat reflux
3. extractionextracted twice with 500 ml of MTBE
4. extractionthe combined organic phases were extracted once with 500 ml of water and once with 500 ml of saturated sodium chloride solution
5. customDrying