Trifluoroacetic acid → Ethyl 4,5,6,7-tetrahydrothieno[3,2-c]pyridine-2-carboxylate

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Reaction Steps

Into a 100-mL round-bottom flask charged with 5-tert-butyl 2-ethyl 6,7-dihydrothieno[3,2-c]pyridine-2,5(4H)-dicarboxylate (1 g, 3.21 mmol; prepared as described in J. Med. Chem. 2006, 49(15):4623-4637) and DCM (16 mL) was slowly added trifluoroacetic acid (1.48 mL, 19.3 mmol) at 0° C. The solution was then stirred at room temperature for 60 min. To the reaction mixture was then added saturated aqueous NaHCO3 solution (10 mL) and DCM (10 mL). Upon separation of the layers, the aqueous solution was further extracted with DCM (20 mL) twice. The combined organic layers were washed with brine, dried over anhydrous MgSO4, and concentrated to give ethyl 4,5,6,7-tetrahydrothieno[3,2-c]pyridine-2-carboxylate (0.547 g, 81%) as an oil. LCMS: (FA) ES+ 212.

Provenance & Evidence