Trifluoroacetic anhydride → Methyl 3-(2-ethoxy-2-oxoethoxy)thieno[2,3-b]pyridine-2-carboxylate 7-oxide

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Reaction Conditions

Reaction Steps

To a mixture of methyl 3-(2-ethoxy-2-oxoethoxy)thieno[2,3-b]pyridine-2-carboxylate (500 mg), urea hydrogen peroxide (239 mg) and CH3CN (8 mL) was added TFAA (0.353 mL) at room temperature. The mixture was stirred at room temperature for 4 h and at 70° C. overnight. To the mixture were added urea hydrogen peroxide (80 mg) and TFAA (0.118 mL). The mixture was stirred at 70° C. for 2 h. After cooling, to the mixture was added saturated aqueous NaHCO3. The resulting precipitate was collected by filtration to give the title compound (246 mg). The filtrate was concentrated. The residue was extracted with EtOAc. The combined organic layer was washed with brine, dried over MgSO4 and concentrated in vacuo to give the title compound (85.1 mg). Total yield: 331 mg.

Provenance & Evidence