Dichloromethane → Ethyl 6-methoxybenzofuran-3-carboxylate

Participants

Reaction Steps

To a solution of 2-hydroxy-4-methoxybenzaldehyde (45 g, 295.76 mmol) in DCM (80 mL) was added catalytic HBF4 etherate (4 mL, 29.4 mmol) and stirred (rt, 10 min). The reaction mixture was cooled (0° C.) and slowly treated drop wise with ethyl diazoacetate (86 ml, 704.7 mmol) over a 30 minute period while maintaining a controlled temperature (0° C. to 23° C.). The resulting mixture was stirred (rt, 1 h). The reaction mixture was concentrated in vacuo and the resulting dark oil was azeotroped with toluene (200 mL) via rotovap (60° C.). Using a Dean Stark trap, the crude mixture was refluxed (24 h). The reaction was cooled (rt) and concentrated in vacuo. The resulting dark oil was purified by flash column chromatography using EtOAc:hexanes (10%) to provide the title compound as a white solid (24.9 g, 38.2%). MS (ESI): mass calcd. for C12H12O4, 220.2; m/z found, 221.2 [M+H]+. 1H NMR (400 MHz, CDCl3): 8.16 (s, 1H), 7.90 (d, J=8.6, 1H), 7.03 (d, J=2.2, 1H), 6.98 (dd, J=6.4, 2.3, 1H), 4.39 (q, J=7.2, 2H), 3.86 (s, 3H), 1.41 (t, J=7.2, 3H).

Provenance & Evidence