Oxalyl chloride → 6-Methoxy-1-benzothiophene-2,3-dione

To a solution of 3-methoxythiophenol (3.75 g, 26.7 mmol) in ether (20 mL) was added oxalyl chloride (3.7 mL, 43 mmol) dropwise. The mixture was heated at reflux for 1.5 h, cooled to rt, and concentrated in vacuo. The resulting yellow oil was dissolved in dichloromethane (50 mL), cooled to 0° C., and was treated with aluminum chloride (4.30 g, 32.0 mmol) in portions. The mixture was heated at reflux for 30 min, cooled to rt, and poured onto ice water with stirring. The organic layer was separated and successively washed with saturated, aqueous sodium bicarbonate, water, and brine. The organic layer was dried over magnesium sulfate, filtered and concentrated in vacuo. The residue was purified by chromatography (4/1 ethyl acetate/hexane) which provided 2.46 g (47%) of 6-methoxy-1-benzothiophene-2,3-dione as an orange solid.

1. temperatureThe mixture was heated
2. temperatureat reflux for 1.5 h
3. concentrationconcentrated in vacuo
4. dissolutionThe resulting yellow oil was dissolved in dichloromethane (50 mL)
5. temperaturecooled to 0° C.
6. temperatureThe mixture was heated
7. temperatureat reflux for 30 min
8. temperaturecooled to rt
9. additionpoured onto ice water
10. customThe organic layer was separated
11. washsuccessively washed with saturated, aqueous sodium bicarbonate, water, and brine
12. dry with materialThe organic layer was dried over magnesium sulfate
13. filtrationfiltered
14. concentrationconcentrated in vacuo
15. customThe residue was purified by chromatography (4/1 ethyl acetate/hexane) which

ORD record

ord-ceffb7e96351488cb85cb0ff167aad90

Source dataset

uspto-grants-2012_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08134003B2