Aluminium lithium hydride → 7-bromo-3-methyl-5-(trifluoromethyl)-1H-indole

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Reaction Steps

Lithium aluminum hydride (16.98 ml, 16.98 mmol) was added to a −40° C. solution of 7-bromo-5-(trifluoromethyl)-1H-indole-3-carbaldehyde (1.24 g, 4.25 mmol) in THF (10 ml). The reaction was stirred between −30° C and −10° C. for 40 min and was quenched with saturated aqueous ammonium chloride (1 mL) and filtered through celite and washed with ethyl acetate (20 mL). The filtrate was evaporated and the residue was purified by chromatography on SiO2 with a gradient of 4% to 30% ethyl acetate/hexanes. The product 7-bromo-3-methyl-5-(trifluoromethyl)-1H-indole (677 mg, 2.435 mmol, 57.3% yield) was obtained as a white solid. 1H-NMR (CDCl3, 400 MHz) δ 8.35 (s, 1H), 7.80(d, J=1.2 Hz, 1H), 7.57 (d, J=0.9 Hz, 1H), 7.12,(q, J=1.2 Hz, 1H), 2.33(d, J=1.2 Hz, 3H). LC (HPLC method 4): tR=3.45 min.

Provenance & Evidence