13414-95-4

4653-11-6

13414-95-4

General procedure: 4-(2-Thienyl)butyric acid (0.75 mmol, 1.0 eq.), trifluoroacetic anhydride (TFAA, 2.25 mmol, 3 eq.), and trifluoroacetic acid (TFA, 0.8 mL) were added to a 10 mL glass reaction vial equipped with a screw cap. The reaction mixture was stirred at room temperature for 12 h. The reaction process was monitored by thin layer chromatography (TLC) or gas chromatography-mass spectrometry (GC-MS). Upon completion of the reaction, the solvent was removed under reduced pressure and the resulting residue was purified by silica gel fast column chromatography (eluent: hexane/ethyl acetate mixed system) to finally obtain the target product 6,7-dihydro-4-keto-5-benzothiophene (6a).