Diethyl malonate

Diethyl malonate (DEM) is the diethyl ester of malonic acid, a colorless liquid with a fruity, apple-like odor naturally found in grapes and strawberries.

Preparation

Reacting chloroacetic acid to cyanoacetic acid using sodium cyanide and subsequent saponification; malonic acid is finally esterified by azeotropic distillation with ethanol in benzene

Taste threshold values

Taste characteristics at 50 ppm: sweet and fruity with apple and pineapple nuances.

Uses

Diethyl malonate is widely used in organic synthesis for producing various compounds, including barbiturates, artificial flavorings, vitamin B1, and vitamin B6. DEM plays a key role in pharmaceutical manufacturing, contributing to the synthesis of drugs like chloroquine and butazolidin, as well as non-steroidal anti-inflammatory agents. It is also utilized in the production of dyes, antioxidants, agrochemicals, and perfumes. In reactions such as the Knoevenagel condensation and 1,4-addition reactions, DEM serves as a versatile intermediate for creating complex organic molecules.

Safety Profile

Mildly toxic by ingestion. A skin irritant. Combustible liquid when exposed to heat or flame; can react with oxidizing materials. To fight fire, use water to blanket fire, foam, CO2, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes. See also ESTERS.

Purification Methods

If too impure (IR, NMR) the ester (250g) is heated on a steam bath for 36hours with absolute EtOH (125mL) and conc H2SO4 (75mL), then fractionally distilled under reduced pressure. Otherwise fractionally distil it under reduced pressure and collect the steady boiling middle fraction. [Beilstein 2 IV 1881.]