Hydrochloric Acid → 1-Benzofuran-5-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

A mixture of 5-bromo-1-benzofuran (0.5 g), Mg (0.92 g, 0.038 mol), I2 (1 crystal) in dry THF (2.5 mL) under N2 atmosphere was refluxed for 30 min. To this was added a solution of 5-bromo-1-benzofuran (4.5 g) in 25 mL of dry THF) as soon as the 12 color disappear and refluxed for another 2 h. The reaction mixture was then cooled to −40° C. and added dry DMF (3.6 g) drop-wise and slowly warmed to RT for a period of 12 h. The reaction mixture was then cooled to 0° C. and acidified with 3N HCl to pH=2 and stirred for 30 min. The reaction mixture was then diluted with water (500 mL), extracted with ethylacetate (2×200 mL), washed with brine and dried. The solvent was removed under vacuum and purified by column chromatography over silica gel (pet. ether/CH2Cl2) to give 5-formyl-1-benzofuran (2 g, 54%) as a liquid. LC-MS: M/Z ESI: 1.47 min, 147.34 (M+1).

Provenance & Evidence