Diethyl Malonate → Diethyl (ethoxymethylene)malonate

Participants

Reaction Conditions

Reaction Steps

160.2 g (1.0 mol) of diethyl malonate, 474.2 g (3.2 mol) of triethyl orthoformate, 4 g of acetic anhydride and 0.5 g of catalyst from Example 1 were initially introduced into the apparatus described in Example 1 and the mixture was heated to boiling. A mixture of 10 g of acetic anhydride and 30 g of triethyl orthoformate were continuously added dropwise in the course of 6 hours. The low-boiling component formed was distilled off at a head temperature of 78° to 79° C. The reaction temperature slowly increased to 159° C. The mixture was kept at this temperature for a further hour. The unreacted orthoester was then distilled off at reduced pressure, the catalyst was filtered off and the crude product was purified by distillation at 0.5 mbar. In this way 205.6 g of diethyl ethoxymethylenemalonate were obtained, which corresponds to a yield of 95.1% of the theoretical yield.

Provenance & Evidence