Dichloromethane → 1,3-Benzodioxole-4-carboxaldehyde

Beteiligte Stoffe

Reaktionsschritte

138.0 g (1.0 mol) of 2,3-dihydroxybenzaldehyde, 415.0 g (3.0 mol) of potassium carbonate, 4.7 g of copper oxide, 255.0 g (3.0 mol) of methylene chloride and 1500 ml of distilled dimethylformamide are boiled for 7 hours, while stirring intensively.. The reaction mixture is evaporated to dryness in vacuo and, after addition of 1000 ml of ice-water to the residue, the mixture is extracted four times by shaking with 300 ml of methyl tert-butyl ether each time. The combined ether extracts are washed with 5% strength sodium hydroxide solution and water and dried over sodium sulphate. The methyl tert-butyl ether is then stripped off (and can be reused) and the residue is distilled in vacuo at 92°-93° C./1 mbar. 120 g (80% of theory) of 2,3-methylenedioxybenzaldehyde having a melting point of 32°-33° C. are obtained.

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