Diisobutylaluminum hydride → (1-Methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)methanol

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Reaction Conditions

Reaction Steps

To a cooled solution (0° C.) of 1-methyl-3-trifluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester (1.0 g, 4.5 mmol) in anhydrous tetrahydrofuran (50 ml), is added a solution of DIBAL-H (20.3 ml, 20.3 mmol). The reaction mixture is stirred at 0° C. for 2 hours and then quenched with saturated aqueous sodium potassium tartrate and stirred for 1 hr. The layers are separated and the aqueous layer is extracted 2 times with ethyl acetate. The combined organic extracts are dried over anhydrous Na2SO4, filtered, and concentrated in vacuo to give 1-methyl-3-trifluoromethyl-1H-pyrazol-4-methanol (1.0 g, 98%) which is used without purification. 1H NMR (CDCl3): δ=7.43 (1H, s), 4.63 (2H, s), 3.90 (3H, s), 2.38 (1H, brs).

Provenance & Evidence