lo6 ORGANIC AGRICULTURAL CHEMISTRY 



The carbohydrates are also directly related to the poly- 

 hydroxy alcohols containing the same number of carbons with 

 a hydroxyl joined to each carbon. By the oxidation of these 

 polyhydroxy alcohols, with the conversion of one alcoholic group 

 only into an aldehyde group or a ketone group, we obtain the 

 carbohydrates. 



This will be clear if we illustrate with a concrete example. 

 The common sugars glucose and fructose each contain six carbon 

 atoms, their formula being C6H12O6. They are both related 

 to the hexa-hydroxy-hexane which is known as sorbitol and which 

 has the constitution as follows : 



OH OH H OH OH OH 



H-C-C-C-C-C-C-H Sorbitol 



H H OHH H H 



When this is oxidized with the conversion of one of the end 



primary alcohol groups into an aldehyde group, we obtain the 



compound : 



O OH H OH OH OH 



C-C-C-C-C-C-H Glucose 



H H OHH H H 



The compound so obtained is the sugar glucose. When, how- 

 ever, the oxidation results in the conversion of one of the sec- 

 ondary alcohol groups into a ketone group, we obtain the com- 

 pound : 



OH O H OH OH OH 



H-C-C-C-C-C-C-H Fructose 



H OH H H H 



This compound is the sugar known as fructose. These two 

 formulas agree with the composition of the two sugars, viz. 

 CeHiaOe or C6(H20)6. The sugars themselves undergo the 



