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

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.

1. temperaturecooling
2. temperaturethe mixture was heated
3. temperatureunder reflux for 15 hrs
4. concentrationThe reaction mixture was concentrated under reduced pressure, saturated sodium hydrogencarbonate solution
5. additionwas added
6. extractionthe mixture was extracted with ethyl acetate
7. washThe extract was washed with water
8. concentrationconcentrated under reduced pressure
9. customThe residue was purified by silica gel column chromatography (hexane/ethyl acetate=9:5 to 4:1)

ORD record

ord-7fee84ef9a124ecaa5cf0f30d5a134ca

Source dataset

uspto-grants-2011_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07960369B2