Phosphorus oxychloride → ethyl 5-chloro-3-formyl-1H-indole-2-carboxylate

Participants

Reaction Steps

Phosphorus oxychloride (2.0 mL) was added to N-methylformanilide (2.9 g), and after the mixture was stirred for 15 minutes, 1,2-dichloroethane (50 mL) and 5-chloroindole-2-carboxylic acid ethyl ester (4.0 g) were added thereto, followed by heating under reflux for 1 hour. The reaction mixture was poured into an aqueous solution (28 mL) of sodium acetate (14 g) under ice cooling, and the thus-obtained mixture was stirred for 18 hours. Insoluble matter was collected by filtration, and was sequentially washed with water and diethyl ether, to thereby give the title compound (3.56 g).

Provenance & Evidence