220 



A. T. RINGER AND EMIL J. J5AUMANN 



which is tho inactive fonn of fructose, so that chemically at least this is a 

 possible mechanism by which plants synthesize carbohydrates. 



'2. Synthesis of higher forms fmw a lower nionoxaccharose. Here, a 

 method of wide application in chemistry has been successfully used to 

 synthesize a large number of carbohydrates. It consists in forming a 

 oyaiihydrin of a lower aldoso with hydrocyanic acid, hydrolyzing the 

 nitrile to form the corresponding acid and reducing this substance to the 

 next higher sugar, e. g. ? glucose may be converted to glucoheptose in this 

 wav. * 



ON 



CH 2 OH 



o-Glucose 



CN 



+ 



H 



Hydrocyanic 

 acid 



no c H 

 IICOH 



HOCH 

 IICOH 

 HCOH 



CH 2 OH 



> ct-Glucose 

 nitrile 



Hydrolysis 



^ 



2 HO 



COOH 



HOCH 



I 

 IICOH 



IIOCH 



I 

 HCOH 



HCOH 



CII.OH 



a^Glucoheptonic 

 Acid 



Reduction 

 with 



sodium 

 amalgam 



C 



|\H 

 HOCH 



HCOII 

 HOCH 

 HCOH 

 HCOH 



CH 2 OH 



a-Glucoheptose 

 Aldehyde Formula 



The ability of hydrocyanic acid to unite with aldoses is of considerable 

 interest physiologically. This acid is found in small amounts in a number 



