Hydrochloric Acid → 3-Cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-5-(1-hydroxy-2,2,2-trifluoroethyl)-4-trifluoromethylthiopyrazole

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Reaction Conditions

Reaction Steps

The product of Example 3 (2.0 g, 0.0046 mol) was dissolved in anhydrous tetrahydrofuran (10 mL). Trifluoromethyltrimethylsilane (0.8 mL, 0.0055 mol) was added and the reaction cooled to 0° C. Tetrabutylammoniumfluoride (TBAF, 50 μL, cat.) was added. After intervals of 20 minutes, 1.5 hours, and 18 hours, aliquots of TBAF (50 μL) were added at 0° C. followed by warming to room temperature. After 21 hours, more trifluoromethyltrimethylsilane (0.8 mL, 0.0055 mol) was added and the reaction stirred for 5 days. This was poured into 10% hydrochloric acid (100 mL) and washed with diethyl ether (3×50 mL). The combined organic extracts were washed with saturated aqueous sodium chloride solution, dried over magnesium sulfate, filtered and evaporated to an oil. This was purified by silica gel chromatography using an ethyl acetate in hexanes gradient to provide the title compound (1.08 g) as a white solid, m.p. about 160° C.

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