Hydrochloric Acid → 5-Acetyl-2-(2,4-dichloro-phenyl)-1h-pyrrole-3-carbonitrile

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Reaction Steps

To a mixture of 2-(2,4-dichloro-phenyl)-1H-pyrrole-3-carbonitrile (6.00 g, 25.30 mmol, see EP 0312,723) in 120 mL of dichloromethane was added acetyl chloride (3.18 g; 40.49 mmol) at room temperature, under nitrogen. The resulting mixture was cooled to +2° C. and anhydrous aluminum trichloride (8.10 g, 60.73 mmol) was added in small portions during a period of 20 minutes, keeping the internal temperature below 5° C. Upon complete addition, the mixture was brought to room temperature and allowed to stir for 3 hours. Then, the mixture was slowly poured in a solution of ice-cooled 2M HCl (120 mL) and isopropanol (28 mL). The aqueous layer was separated and extracted twice with a mixture of dichloromethane (120 mL) and isopropanol (28 mL). The combined organic extracts were concentrated under reduced pressure to slurry, which was treated under stirring with isopropanol (30 mL) and diluted with water (60 mL) at room temperature. The solid was collected by suction and dried under vacuum at +50° C. to afford the 6.51 g of product as white, fluffy crystals. Yield=92%.

Provenance & Evidence