226 



A. I. RINGER AND EMIL J. BAUMANN 



which is the inactive form of fructose, so that chemically at least this is a 

 possible mechanism by which plants synthesize carbohydrates. 



2. Synthesis of higher forms from a lower monosaccharose. Here, a 

 method of wide application in chemistry has been successfully used to 

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

 cyanhydrin of a lower aldose 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 

 way. 



ON 



CH 2 OH 



o-Glucose -f- Hydrocyanic 

 acid 



COOH 

 HOCH 



HO C H 



HCOH 



HOCH 



HCOH 



HCOH 



CH 2 OH 



> a-Glucose 

 nitrile 



Hydrolysis 



2 HO 



/O 



HCOH 

 HOCH 

 HCOH 



HCOH 



I 

 CH 2 OH 



a-Glucoheptoiiic 

 Acid 



Reduction 

 with 



[ N 



sodium 

 amalgam 



C 



I 



HOCH 



I 

 HCOH 



HOCH 



HCOH 



I 

 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 



