Lithium borohydride → 7-(1-Methylethyl)-1H-indole

Participants

Reaction Conditions

Reaction Steps

To a solution of 7-isopropyl-1H-indole-2,3-dione (2.97 g, 15.7 mmol) in tetrahydrofuran (20 mL) was dropped 2.0 M solution of lithium borohydride in tetrahydrofuran (15 mL, 30 mmol). The mixture was heated at 90° C. for 4 hours. It was quenched with 5% HCl, followed by saturated sodium bicarbonate. It was extracted with ethyl acetate. The extracts were dried over magnesium sulfate and evaporated to dryness to provide a crude 7-isopropyl-1H-indole. To a solution of the crude 7-isopropyl-1H-indole in diethyl ether (40 mL) was dropped 2.0 M solution of oxalyl chloride in dichloromethane (15 mL, 30 mmol). After stirring at room temperature for 5 hours, it was evaporated to dryness. Ethanol was added to the residue and it was stirred at room temperature overnight. After the ethanol was evaporated, flash chromatography on silica gel provided 0.972 g (24%) of the title compound as solid. ESI (−) MS m/e=258 (MH−).

Provenance & Evidence