io6 



Biological Chemistry. 



of the primary alcohol group, CH 2 OH, to a carboxyl 

 group (compare p. 70). Oxalic acid can be produced by 

 the oxidation of ethylene glycol, which contains two 

 primary alcoholic groups 



CH 2 OH CO OH 



CH 2 OH CO -OH 



In this reaction aldehydes can be formed as intermediate 

 products, as might be expected, and one or both of the 

 alcoholic groups can undergo oxidation ; in fact, a whole 

 series of intermediate oxidation products might be expected 

 to be formed (and, as a matter of fact, are formed) in the 

 process, the formulae of which are here given 



CH 2 OH CHO CO OH COOH COOH 



CHO 



Glyoxal. 



The above offers a very good example of the general 

 nature of chemical reactions, and illustrates in a striking 

 way the method of oxidation of a primary alcoholic group. 



The following are some of the chief acids of the oxalic 

 acid series : 

 OxaHcacid, COOH OOOH 



CO 



OH 

 Malonic acid, CO OH 



CHj 



CO. 



rf 



h y drated form COOH 

 melting point, 132' 



OH 



