Trifluoroacetic acid → N-{4-[4-(4-chlorophenyl)-4,5,6,7-tetrahydro-1-benzothien-2-yl]pyridin-2-yl}acetamide

In a 100 mL round bottomed flask was placed crude N-{4-[4-(4-chlorophenyl)-4-hydroxy-4,5,6,7-tetrahydro-1-benzothien-2-yl]pyridin-2-yl}acetamide (410 mg, 1.0 mmol) prepared above and 1,2-dichloroethane (10 mL). The mixture was refluxed for 30 min to obtain a yellow solution. To the refluxing mixture were added triethylsilane (1 mL, 6 mmol) and trifluoroacetic acid (2 mL, 20 mmol), and refluxing was continued for an additional 3 hr. The mixture was allowed to cool to rt then concentrated under reduced pressure. The residue was diluted with EtOAc (50 mL) then washed with a saturated aqueous solution of NaHCO3 (50 mL). The aqueous phase was extracted with EtOAc (50 mL). The combined organic phases were dried over anhydrous MgSO4.