CONSTITUTION 169 



assume that the original glucoside was formed by a reaction 

 similar to the one given for the artificial glucosides mentioned 

 above, that is by the elimination of water between a hydroxyl 

 group of the sugar and one from the other compound. On 

 this assumption the constitution of some of the better known 

 natural glucosides could be represented as follows : 



CH 2 OH CHOH CH CHOH CHOH CH . OH + HOC 6 H 4 CH 2 OH 

 Glucose Saligenin 



= CH 2 OH CHOH CH CHOH CHOH CH . O . C 6 H 4 CH 2 OH + H 2 O 



SALICIN 



:H 2 OH CHOH CH CHOH CHOH CH . OH + HOC 6 H 4 OH 



Glucose Hydroquinone 



CH 



ARBUTIN 



OH CHOH CH CHOH CHOH CH . O . C 6 H 4 OH + H 2 O 



IN 



C 6 H 5 

 :H 2 OH CHOH CH CHOH CHOH CH . OH + 



CN 

 Glucose Mandelonitrile 



= CH 2 OH CHOH CH . CHOH CHOH CH O CH + H 2 O 



CN 

 PRUNASIN, PRULAURASIN or SAMBUNIGRIN 



In some cases the natural glucosides have been actually 

 ithesized ; thus salicin has been obtained by the reduction 

 of the corresponding aldehyde glucoside, helicin : 



C 6 H n 5 .O.C 6 H 4 CHO + 2 H = C 6 H U O 5 .C). C 6 H 4 CH 2 OH 



the helicin itself having been synthesized from glucose and 

 salicylic aldehyde. 



Identification. 



For the identification of glucosides the character of the 

 cleavage products are relied upon ; these products, with the 



