Acetic Acid → (5-Formyl-2-methyl-benzofuran-3-yl)-acetic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

A mixture of (5-cyano-2-methyl-benzofuran-3-yl)-acetic acid ethyl ester (4.31 g, 17.7 mmol), NaPH2O2.H2O (14.99 g, 141 mmol) and Raney nickel (3.06 g, 35.4 mmol) in a mixture of water (50 mL), acetic acid (50 mL) and pyridine (100 mL) is heated for 2 h at 100° C. under an argon atmosphere. After cooling to room temperature the reaction mixture is filtered over hyflo and the filtrate concentrated by rotary evaporation. The residue is partitioned between water and TBME, the layers are separated and the aqueous phase is extracted with TBME. The combined organic layers are washed with a 1 M aqueous HCl solution, a saturated aqueous NaHCO3 solution and brine. After drying over Na2SO4 and evaporation of the solvent in vacuo the crude product is obtained as a brown oil. Further purification by flash column chromatography (silica gel gradient of cyclohexane/EtOAc 100:0 to 6:1) affords the title compound as colorless crystals (2.59 g, 10.5 mmol, 60%). 1H NMR (400 MHz, CDCl3, 298 K): δ=10.08 (s, 1H), 8.07 (s, 1H), 7.82 (d, J=8.9 Hz, 1H), 7.52 (d, J=8.9 Hz, 1H), 4.19 (q, J=7.1 Hz, 2H), 3.66 (s, 2H), 2.49 (s, 3H), 1.27 (t, J=7.1 Hz, 3H). MS (ES+): 247 (M(C14H14O4)+H)+.

Provenance & Evidence