Acetic Anhydride → 3-Acetyl-1-benzenesulfonylindole-5-carboxylic acid methyl ester

Participants

Reaction Steps

To a suspension of 10.7 g (80 mmol) of aluminum chloride in dichloroethane (80 ml) was added dropwise 4.83 g (40 mmol) of acetic anhydride. After stirring for 15 min, to the mixture was added dropwise 6.31 g (20 mmol) of the above-mentioned 1-benzenesulfonylindole-5-carboxylic acid methyl ester in dichloroethane (60 ml). After stirring for 2 hours at room temperature, to the mixture were added 5.33 g (40 mmol) of aluminum chloride and 2.04 g (20 mmol) of acetic anhydride. After stirring for 30 min, the mixture was poured into ice-water, extracted with ethyl acetate. The extract was washed twice with water, aqueous sodium bicarbonate and dried, and then concentrated. The obtained crystal was washed with isopropyl ether to give 6.82 g of 3-acetyl-1-benzenesulfonylindole-5-carboxylic acid methyl ester. Yield: 96%.

Provenance & Evidence