Hydrochloric Acid → 1-(2-Fluoro-4-chloro-5-hydroxyphenyl)-3,4,5-trimethylpyrazole

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Reaction Conditions

Reaction Steps

A mixture of 1-(2-fluoro-4-chloro-5-methylsulfonyloxyphenyl)- 3,4,5-trimethylpyrazole (33.3 g), 2N aqueous sodium hydroxide (100 ml) and ethanol (50 ml) was stirred at 40° C. for 30 minutes. After cooling, the reaction mixture was acidified with aqueous hydrochloric acid and then extracted wth toluene. The toluene layer thus obtained was washed with water and dried over anhydrous sodium sulfate. Removal of the solvent by distillation in vacuo gave the titled compound (24.2 g) as a pale yellow crystalline solid. Recrystallization of this solid from a mixture of n-hexane/ethyl acetate yielded a white crystalline solid. m.p. 158°-160° C.

Provenance & Evidence