Acetic Anhydride → HCID 11770291, compound

Participants

Reaction Conditions

Reaction Steps

Aluminum chloride (7.75 g, 0.058 mol) was suspended in 200 ml of anhydrous dichloroethane at room temp. followed by a slow addition of acetic anhydride (2.74 mL, 0.03 mol). The mixture was stirred at room temp for 10 minutes after which, 1H-indole-2-carboxylic acid ethyl ester (1b, 5.0 g, 0.0264 mol) was added as a solution in 15 mL of dichloroethane. The reaction mixture was stirred under nitrogen at 40° C. for 10 h. The reaction was quenched with an ice-water mixture and the organic layer was washed with water (3×). The organic phase was dried over anh. Na2SO4, filtered and concentrated in vacuo. Chromatography on SiO2 (4% Ethyl acetate/96% CH2Cl2) provided 3.2 g of 3-acetyl-1H-indole-2-carboxylic acid ethyl ester 2b (52%) and 770 mg of 5-acetyl-1H-indole-2-carboxylic acid ethyl ester 3b (13%).

Provenance & Evidence