88 THE CARBOHYDRATES 



DISACCHARIDES PRODUCED BY THE UNION OF 

 A HEXOSE WITH A PENTOSE. 



Of late years several disaccharides have been discovered 

 which on hydrolysis yield one molecule each of a hexose and 

 a pentose ; such are the two glucoxyloses isolated in the form 

 of their dibenzoyl derivatives from a bitter principle contained 

 in Daviesia latifolia* 



Three other glucoxyloses are given below : 



PRIMEVEROSE. C U H 20 O 10 . 



Primeverose is prepared from the glucosides primeverin and 

 primulaverin occurring in Primula officinalis.\ It has a free 

 aldehyde group and would therefore appear to have the con- 

 stitution, 



CHO.[CHOH] 4 .CH 2 .O.CH.CH.[CHOH] 2 .CH 2 OH 



V 



O 



VICIANOSE. C n H 20 O 10 . 



This disaccharide is obtained by the hydrolysis of the 

 glucoside vicianin occurring in Vicia angustifolia, and is found 

 to be composed of one molecule of glucose and one of 

 arabinose.| 



STROPHANTHOBIOSE. C 12 H 22 O 10 . 



This disaccharide likewise occurs in a glucoside, stro- 

 phanthin. On hydrolysis it yields mannose and rhamnose 

 (C 6 H 12 5 ). 



TRISACCHARIDES. 

 RAFFINOSE. 



This sugar occurs in cotton seeds, barley, eucalyptus, 

 manna, jute, and in the beetroot ; the juice of this latter con- 

 tains on an average about 1 5 per cent of cane sugar but only 

 O'O2 per cent II of raffinose. The molasses from beet sugar re- 



* Power and Salway : " J. Chem. Soc.," 1914, 1069. 



f Goris and Vischniac : " Compt. rend.," 1919, 169, 871, 975. 



J Bertrand and Weisweiller: id., 1910, 151, 325, 884. 



Feist : " Ber. deut. chem. Gesells," 1900, 33, 2091. 



|| Strohtner : " Oest. Ung. Z. f. Zuckerind. u. Landw.," 1910, 39, 649. 



