Aluminium lithium hydride → 1-Methyl-4-(trifluoromethyl)-1H-pyrazole-3-methanol

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Reaction Steps

Lithium aluminium hydride (1M in THF) (11 ml, 11 mmol) was added dropwise to a solution of 1-methyl-4-trifluoromethyl-1H-pyrazole-3-carboxylic acid (1.94 g, 10 mmol) in THF (20 ml) under nitrogen. More THF (20 ml) was added to facilitate the stirring. After stirring for 5 hours at room temperature the reaction was quenched by addition of water (0.5 ml), 15% aqueous sodium hydroxide (0.5 ml), and more water (0.5 ml). Ethyl acetate (50 ml) and magnesium sulfate (25 g) were added and the mixture stored at room temperature for 18 hours. Kieselguhr (30 g) was added, the mixture filtered and the solids washed with ethyl acetate. The combined filtrate and washings were concentrated to give the product as a pale yellow oily solid (1.38 g, 77% yield). 1H-NMR (400 MHz, CDCl3): 2.3 (1H, bs, OH), 3.91 (3H, s, Me), 4.75 (2H, s, CH2), 7.62 (1H, s, CH).

Provenance & Evidence