SOME RESEARCH PROBLEMS IN THE 

 CARBOHYDRATES. 



AUDliESS (part II) TO SKCTION B ( CIIEMISTKY) BY 



riuxciPAL J. 0. IRVINE, C.B.E., D.Sc, LL.D., E.E.S., 



PliKSIDKXT Ol'' THE SECTION. 



CELLULOSE, STARCH. AND INULIN. 



In subuiiLtiiig at this stage an account of the researches upon wJiich 

 my co-workers arc at present engaged, I am impressed by the recoUeo 

 tion that the first paper on the alkyhition of sugais was read to Section B 

 twenty years ago. The connnunication^ dealt merely with the progres- 

 sive methylation of methylglucoside and with the trimethyl and tetra- 

 methyl glucoses to which the products give rise. Even at that time it 

 was recogTiised that the study of methylated sugars opened up a new 

 method of attacking the constitutional prohlems of the carbohydrates, 

 and the further progress reported to the Association in the following 

 year showed how the process could be applied to determine, in part, the 

 structm-e of sucrose and maltose.- The principle underlying these 

 studies may be very briefly stated. Adopting for the moment the 

 accepted foiTnula for glucose it will be seen that a hexose sugar contains 

 five hydroxyl groups: — 



I. 



— CHOH 1. 



I 



CHOH 2. 



O I 



CHOH 3. 



— CH 4. 



I 



CHOH 5. 



I 

 CH.OH 6. 



It is to be noted that one of these groups differs from the remaining 

 four in that, although it may be replaced by a. methyl group, this is 

 easily removed by acid hydrolysis. On the other hand, when methyl 

 groups are introduced into the remaining positions (numbered 2, 3, 

 5, and 6 in the formula), they are exceedingly resistent to hydrolytic; 

 action. It follows, therefore, that a fully methylated glucoside (11.) 

 when lieated witli acid will be converted into a tetramethvl glucose 

 (ITT.). 



II. III. 



—CHOCK, ,— CHOH 



I I 



CHOCH, CHOCH, 



1 1 

 CHOCH, 



-CH 



CHOCH, 

 I 

 -CH 



CH0C:H, CHOCH., 



I I 



CHjOCH, CH.OCH, 



E 'Z 



