Carbon Dioxide → 5-(3,4-Dimethoxyphenyl)furan-2-carbaldehyde

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Reaction Steps

A 12 l. four-necked flask equipped with a stirrer, a thermometer and a dropping funnel was charged with water (5 l.). Hydrochloric acid (500 ml) was introduced dropwise. 3,4-dimethoxyaniline hydrochloride (379 g, 2.0 moles) was introduced. This mixture was cooled to -5° C. with a mixture of dry ice and acetone. A solution of sodium nitrite (200 g, 2.9 moles) in water (1600 ml) was introduced dropwise maintaining the temperature at -5° to 0° C. This was followed by the addition of furaldehyde (384 g, 4.0 moles) at -5° C. as fast as possible. A solution of CuCl2.2H2O (112 g) in water (500 ml) was introduced. Stirring was continued for 8 days at ambient temperature. The contents of the flask was extracted with ether (3×3 l.). The combined extracts were dried over MgSO4 overnight. The mixture was filtered and the drying agent was washed with anhydrous ether. The solvent was removed in vacuo. The excess furfural was removed by using an oil pump and a water bath having a maximum temperature of 63° C. The residue was triturated with a minimum amount of isopropanol and ice cooled. The semi-solid was filtered off and washed with isopropanol. The obtained solid was stirred with fresh isopropanol (500 ml) and filtered to give 125 g of the product (27%).

Provenance & Evidence