Nitric Acid → 1-Methyl-5-difluoromethoxy-4-chloro-3-(2-fluoro-4-chloro-5-nitrophenyl)pyrazole

Participants

Reaction Conditions

Reaction Steps

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.

Provenance & Evidence