Bromoacetyl chloride → 2-Bromo-1-(5-bromo-1H-pyrrolo[2,3-b]pyridin-3-yl)ethan-1-one

Participants

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. Then bromoacetyl chloride (11 ml, 126.2 mmol) in dichloromethane was added drop wise and the reaction was allowed to proceed at room temperature overnight. The next day the reaction was cooled to 0° C. and was quenched with methanol (˜30 ml) until the reaction turned clear. The reaction was concentrated under vacuum and resuspended in water (300 ml). The pH was adjusted to 7 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, brine, dried with Na2SO4. Silica chromatography of the crude using a gradient of ethyl acetate and hexane afforded 2-bromo-1-(5-bromo-1H-pyrrolo[2,3-b]pyridin-3-yl)-ethanone (7.4 g, 92% yield). 1H NMR (500 MHz, DMSO-d6) δ 4.76 (s, 2H), 8.45 (s, 1H), 8.61 (s, 1H), 8.75 (s, 1H), 12.98 (s, 1H). MS: m/z 318.8 (M+H+).

Provenance & Evidence