194 A GENERAL REVIEW OF 



glucose, but tetramethyl /3-methylglucoside (25). The changes 

 described are represented as follows : 



CHOCH 3 



CHOH 

 CHOH 



O 



CHOH 



CHOH 



CHOCH 3 

 CHOCH 3 

 CHOCH 



,CHOH 



CHOCH 3 



CHOCH 3 



CHOCH, 



/ CHOCH 3 



| 



\ CHOCH, 



CH 



CHOCH, 



\ 



CHOCH 3 

 CH.OCH, 



(7-oxidic) Tetramethyl 



Tetramethylglucose. a- and /3-methylglucosides. 



.CHOH 



CHOCH 3 



CHOCH 3 



CH 



CHOCH 3 



CH,OH 



(7-oxidic) 

 Trimethylglucose. 



It has not yet been ascertained which of the hydroxyl 

 groups in a-methylglucoside remains unalkylated when it is 

 converted into trimethyl a-methylglucoside, and hence the 

 formula given for the latter substance may not be strictly 

 accurate as regards the positions of the substituent methyl 

 groups. Work at present being conducted by Professor Irvine 

 tends to show, however, that the view adopted is correct. 



On oxidation by Kiliani's method, tetramethyl glucose 



