反应详情

温度

0 °C

A mixture of 18.0 grams (0.058 mole) of 1-methyl-5-difluoromethoxy-4-chloro-3-(2-fluoro-4-chlorophenyl)pyrazole and 120 mL of concentrated sulfuric acid was stirred, and when the pyrazole was dissolved, the solution was cooled to 0° C. To this was added dropwise 5.5 mL (0.074 mole) of 70% nitric acid at a rate to maintain the reaction mixture temperature below 3° C. Upon completion of addition the reaction mixture was allowed to warm to about 10° C. where it stirred for two hours. After this time the reaction mixture was poured into ice-water and then extracted with several portions of diethyl ether. The combined extracts were dried with magnesium sulfate and filtered. The filtrate was concentrated under reduced pressure, yielding 20.1 grams of 1-methyl-5-difluoromethoxy-4-chloro-3-(2-fluoro-4-chloro-5-nitrophenyl)pyrazole. The NMR spectrum was consistent with the proposed structure.

1. temperatureto maintain the reaction mixture temperature below 3° C
2. additionUpon completion of addition the reaction mixture
3. temperatureto warm to about 10° C. where it
4. stirringstirred for two hours
5. extractionextracted with several portions of diethyl ether
6. dry with materialThe combined extracts were dried with magnesium sulfate
7. filtrationfiltered
8. concentrationThe filtrate was concentrated under reduced pressure