Thiophene → 4H,5H,6H-cyclopenta[b]thiophen-4-one

Participants

Reaction Steps

To a solution of N,N-dimethylacrylamide (6.6 g, 71 mmol) in dichloroethane (400 ml) was gradually added dropwise a solution of trifluoromethanesulfonic acid anhydride (20 g, 71 mmol) in dichloroethane (50 mL) under ice-cooling. A solution of thiophene (6.0 g, 71 mmol) in dichloroethane (50 mL) was added to the mixture, and the mixture was heated under reflux for 15 hrs. The reaction mixture was concentrated under reduced pressure, saturated sodium hydrogencarbonate solution was added, and the mixture was extracted with ethyl acetate. The extract was washed with water and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate=9:5 to 4:1) to give the title compound (3.8 g, yield 39%) as a white powder.

Provenance & Evidence