Chemical Properties
colourless liquid
Chemical Properties
Diethyl malonate has a faint, pleasant, aromatic odor.
Occurrence
Reported found in pineapple, bilberry, Cape gooseberry, cognac, malt whiskey, apple brandy, grape brandy,
port, cider, sherry and red, white, strawberry and bilberry wines.
Uses
Diethyl Malonate occurs naturally in grapes and strawberries. It is used in the preparation of barbiturates, artificial flavourings, vitamin B1, and vitamin B6 as well as in perfumes.
Uses
manufacture of barbiturates.
Definition
ChEBI: Ethyl malonate is a dicarboxylic acid.
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.
General Description
Diethyl malonate is diethyl ester of malonic acid. Acylation of diethyl malonate using magnesium chloride and triethylamine is reported. K2CO3-catalyzed 1,4-addition reaction of diethyl malonate with various substituted 1,2-allenic ketones yields polyfunctionalized β,γ-unsaturated enones.
Metabolism
When the ester was fed to chicks at a level of 5% in the diet, 32% of the energy from diethyl malonate was available (Yoshida et al. 1970). Hydrolysis of diethyl malonate would produce ethanol and malonic acid, which is a relatively strong acid and acts as an inhibitor of enzymes, including succinic dehydrogenase (Fassett, 1963). Malonic acid injected into rats or rabbits is excreted largely unchanged, but also causes increased excretion of citric and a-ketoglutaric acids (Krebs, Salvin & Johnson, 1938). Some malonate may be metabolized through the tricarboxylic acid cycle, with decarboxylation to acetate followed by transformation to succinate, which has been detected in rat urine (Lee & Lifson, 1951). Diethyl malonate was hydrolysed by adipose-tissue lipase (Lynn & Perryman, 1960) and to the monoester by α-chymotrypsin (Cohen & Crossely, 1964). It was oxidized in 110 min to the extent of 34% by the homogenized mycelium of urethane-grown Streptomyces nitrifica (Schatz, Trelawny, Schatz & Mohan, 1957).
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.]
Toxics Screening Level
RTECS listed an acute oral study for this material, Smyth et al (1969), who reported a rat LD50 of 15 g/kg. As this is the only available toxicity data, the ITSL will be based on the LD50 of 15 g/kg and calculated as follows, ITSL=(15000 mg/kg)x(1/500 X 1/40 X 1/100 X 1/.167 X 1/.9)= 50 ugfm3 an annual average.
