MM. Zwenger and Dronke on a new Glucoside. 4>77 



of the liquid, robinine separates out in yellowish crystals, and is 

 purified by repeated recrystallizations from water. 



It is a neutral substance, with a feeble astringent taste. Very 

 soluble in hot water, it is slightly soluble in alcohol, and inso- 

 luble in ether. It melts at 195°, and solidities to an amorphous 

 mass. It is dissolved by alkaline solutions with a fine golden- 

 yellow colour. It readily reduces an alkaline solution of oxide 

 of copper, and also chloride of gold. 



It is readily decomposed by boiling with dilute hydrochloric 

 acid, with the separation of quercetine, while the solution contains 

 sugar. Emulsine does not produce this change. This decom- 

 position reveals a connexion between this new glucoside and quer- 

 citrine; both of them yield quercetine by decomposition, but 

 differ in the nature of the saccharine substances which they con- 

 tain as a copulate. This is the first instance of the kind in which 

 such a difference occurs in the glucoside. Zwenger and Dronke 

 have prepared quercetine by the decomposition of quercitrine, 

 and found that this is quite identical with the body prepared 

 from robinine. 



Robinine, dried at 100°, has the formula C 50 H 30 O 32 ; dried 

 in the air its formula is C 50 H 41 O 43 , containing 11 equivalents 

 of water of crystallization. The formula of quercitrine was found 

 to be C 38 H 18 O 20 . 



The decomposition of robinine is expressed by the following 

 equation : — 



C 5o H so 3 2 + 4HO = C 26 H 10 O 12 + 2(C 12 H 12 12 ) 



Robinine. Quercetine. Sugar. 



and that of quercitrine thus : — 



C 38 H 18 O 20 + 7HO = C 26 H 10 O 12 -hC 12 H 15 O 15 . 



Quercitrine. Quercetine. Sugar. 



Quercitrine, in almost all its physical and chemical character- 

 istics, is different from robinine — more especially in its difficult 

 solubility in hot water, in its being precipitated by acetate of 

 lead, and in its crystalline form ; and the only similarity is the 

 elimination of quercetine by both bodies when treated with acids. 



The sugar from quercitrine forms yellowish crystals with a 

 sweet taste, reduces alkaline solution of sulphate of copper even 

 in the cold, and, mixed with yeast, passes into the spirituous 

 fermentation. By oxidation with nitric acid it yields oxalic acid 

 alone. The robinine sugar, on the contrary, does not crystal- 

 lize ; it however reduces oxide of copper in solution of potash 

 even in the cold, and, mixed with yeast, passes into the alcoholic 

 fermentation. Oxidized with nitric acid it yielded principally 

 picric acid, and was thus different from quercitrine sugar. 



From the great analogy which a number of glucosides present, 



