Acetyl chloride → 1-(5-bromo-1H-pyrrolo[2,3-b]pyridin-3-yl)ethanone

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Reaction Steps

5-Bromo-1H-pyrrolo[2,3-b]pyridine (5 g, 25.2 mmol) was added to aluminum chloride (16.8 g, 126.2 mmol) in dichloromethane (200 ml) under nitrogen. The mixture was allowed to stir at room temperature for 1 hour. Acetyl chloride (9 ml, 126.2 mmol) in dichloromethane was added drop wise and the reaction was allowed to proceed at room temperature overnight. Next day the reaction was cooled to 0° C. and quenched with methanol (˜500 ml) until the reaction turned clear. The reaction was concentrated under vacuum and resuspended in water (300 ml). The pH was adjusted to 4 with 7N sodium hydroxide solution and then extracted with ethyl acetate (300 ml×3). The combined organic layers were extracted with saturated sodium potassium tartrate and brine and dried with Na2SO4. Silica chromatography of the crude using a gradient of ethyl acetate and hexane afforded 1-(5-bromo-1H-pyrrolo[2,3-b]pyridine-3-yl)-ethanone (5.2 g, 87% yield). 1H NMR (500 MHz, DMSO-d6) δ 2.48 (s, 3H), 8.41 (s, 1H), 8.57 (s, 1H), 8.58 (s, 1H). MS: m/z 241.0 (M+H+).

Provenance & Evidence