PURDIE'S REACTION 203 



DETERMINATION OF THE CONSTITUTION OF SUGAR 

 DERIVATIVES BY MEANS OF THE ALKYLATION PROCESS 



Reference has already been made to the evidence, obtained 

 by means of the silver oxide reaction, bearing on the con- 

 stitution of methylglucoside, sucrose, and maltose. These 

 and other similar applications of the reaction have been 

 collated by Irvine in a paper in the Biochemische Zeitschrift 

 (50), which gives a useful summary and bibliography of such 

 results of this nature as had been obtained prior to September 

 1909. 



Of the natural glucosides, only salicin and gynocardin 

 have so far been investigated by means of the reaction. 

 The results obtained by Irvine and Rose (32) in the former 

 case are of great interest, and show that salicin is constituted 

 similarly to the artificial glucosides. By alkylation of the 

 glucoside in the usual manner, a crystalline pentamethyl salicin 

 was obtained. The hydrolysis of this compound by dilute 

 aqueous acid led to the production of resinous substances 

 which could not be further examined ; it was therefore impos- 

 sible to obtain evidence of constitution in this way. The 

 following synthetic evidence, however, demonstrated the 

 presence of the y-oxidic linkage in salicin. Saligenin and 

 tetramethyl glucose were dissolved in benzene containing 0*25 

 per cent, of hydrogen chloride, and the solution was heated 

 in sealed tubes at 120 C. A syrupy, glucosidic condensation 

 product resulted, which in all probability was a mixture of 

 the a- and /3-forms of tetramethyl salicin : 



CH 2 (OH) . C 6 H 4 . . CH . (CH . OCH 3 ) 2 . CH . CH . (OCH 3 ) . CH 2 OCH 3 . 



' 



The hydroxyl group remaining in this product was now 

 alkylated, when a crystalline pentamethyl salicin resulted and 



