Hydrochloric Acid → 5-Hydroxy-2-(4-hydroxy-phenyl)-7-methoxy-benzofuran-4-carbaldehyde

Participants

Reaction Steps

A solution of 62 (0.25 g, 1.0 mmol) in DMF (20 mL) was treated with POCl3 (1 mL, 11 mmol) and heated at 80° C.–100° C. for 15 minutes. The reaction mixture was worked up by allowing to cool and then poured into crushed ice. 2N NaOH aq was added and the solution stirred for several minutes and then the mixture was acidified with 2N HCl aq and then neutralized with NaHCO3 aq. The mixture was then extracted with EtOAc and washed with brine, dried over MgSO4, filtered, concentrated and chromatographed on silica gel (2:8 to 4:6 EtoAc/hexanes) to yield a solid which still contained some starting material, but that was purified by trituration with EtOAc to yield 47 mg the desired pdt as a white solid: Mp=254–255° C.; 1H NMR (DMSO-d6) δ 10.29 (s, 1 H), 10.0 (br s, 1 H), 7.73 (d, 2 H, J=8.7 Hz), 7.59 (s, 1 H), 6.88 (d, 2 H, J=8.7 Hz), 6.46 (s, 1 H), 4.00 (s, 3 H); MS 281 (M−H)−.

Provenance & Evidence