1 1 8 Biological Chemistry. 



hydroxy derivative of succinic acid. It can be obtained 

 synthetically from the latter acid, which is first treated 

 under certain conditions with bromine. The bromo 

 derivative 



CHBr-COOH 



)H 2 COOH 



is thereby obtained, which when warmed with water and 

 silver hydroxide gives malic acid 



CHBr-CO-OH CH(OH) CO OH 



CH 2 -CO OH + CH 2 CO OH 



Malic acid is a crystalline acid, melting point 100, which 

 is easily soluble in water. 

 Tartaric acid 



CH(OH)COOH 



CH(OH)-COOH 



is dihydroxy tartaric acid. This is also an acid which is 

 widely distributed in plants. In the later stages of grape 

 fermentation, the so-called " argol " is deposited, which is 

 the acid potassium salt of tartaric acid ; and this is the 

 principal commercial source of the acid. Like lactic acid 

 it also occurs in optically active isomeric forms (see 

 Chap. IV.), and certain aspects of its chemistry will be 

 considered in a later chapter. It can be prepared from 

 succinic acid, through the intermediation of its dibromo 

 derivative. 



When succinic acid is treated with bromine under 

 certain experimental conditions (different to those required 

 for obtaining the mono-brom derivative) a substance 



CHBr CO OH 

 HBr-COOH 



