Cesium carbonate → Ethyl 4-{4-[(dimethylamino)sulfonyl]-3-fluorophenoxy}-2-methyl-1-benzofuran-6-carboxylate

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Reaction Conditions

Reaction Steps

A mixture of ethyl 4-hydroxy-2-methyl-1-benzofuran-6-carboxylate (500 mg, 2.27mmol), 2,4-difluoro-N,N-dimethylbenzenesulfonamide (553 mg, 2.75 mmol), Cs2CO3 (1.1 g, 4.12 mmol) and CuI (100 mg, 1 mmol) in DMF (20 mL) was heated to 100° C. for 4 hours. The solvent was removed under reduced pressure. The residue was poured into water (20 mL) and extracted with EtOAc (50 mL×2). The combined organic layers was washed with brine (20 mL×2), dried over Na2SO4 and concentrated. The product was purified via gradient silica gel column chromatography using EtOAc/Hex (10/90 to 30/70) to afford the desired compound (850 mg, 91%) as a white solid. 1H NMR (300 MHz, CHLOROFORM-d) δ ppm 1.41 (t, J=7.16 Hz, 3 H) 2.48 (s, 3 H) 2.78-2.94 (m, 6 H) 4.40 (q, J=7.10 Hz, 2 H) 6.24 (s, 1 H) 6.66-6.94 (m, 2 H) 7.65 (s, 1 H) 7.79 (t, J=8.38 Hz, 1 H) 8.04 (s, 1 H); MS (ESI, pos): 422.

Provenance & Evidence