U4 PRACTICAL ORGANIC AND BIO-CHEMISTRY 



COOH 



I CH 3 



CH =C0 2 + I 



COOH. 

 COOH 



The diethyl ester of malonic acid is a compound much used for 

 the synthesis of other organic compounds. 



COMPOUNDS CONTAINING FOUR CARBON ATOMS. 



The vegetable acids, malic and tartaric, and the two acids, yS- 

 hydroxybutyric and acetylacetic, which are found in urine in cases of 

 diabetes are the chief biological representatives of this group of com- 

 pounds. Succinic acid is the dibasic acid of this series ; malic acid is 

 monohydroxy-succinic acid ; tartaric acid is dihydroxy-succinicacid : 



CH 8 

 CO 

 CH 2 



COOH 



Acetyl- 

 acetic acid. 



Succinic Acid. 



Succinic acid occurs in certain lignites and fossils, in lettuce, unripe 

 grapes and other fruits. It has also been found in animal tissues 

 and meat extracts. 



Succinic acid is obtained by the dry distillation of amber. The 

 aqueous distillate is filtered whilst hot to separate oil, and on cooling 

 crystals of succinic acid are deposited. They may be purified by boiling 

 with nitric acid and recrystallisation. 



Succinic acid is usually prepared by the fermentation by yeast of 

 calcium malate or ammonium tartrate. It is formed by the reduction 

 of these compounds. 



Succinic acid crystallises in colourless prisms or plates which melt 

 at 182. On heating, it emits suffocating fumes; at higher tempera- 

 tures it boils and gives a sublimate of succinic anhydride. 



It is not readily soluble in cold water, but dissolves readily in 

 alcohol and sparingly in ether. It is insoluble in chloroform and 

 benzene. 



