528 M. Strecker on Caffeine. 



acetic acid, € 2 H 4 2 . Kekule has shown* that the latter acid 

 mav be transformed into the former by a method which has since 

 then received extensive applications to other acids. It consists 

 in first replacing an atom of hydrogen by chlorine, iodine, or 

 bromine, and then treating this body by potash, or oxide of silver 

 and water, by which the atom of hydrogen is replaced by HO. 

 H. Strecker f has applied this reaction to cinchonine in the ex- 

 pectation of changing it into quinine. Bibrominated cinchonine, 

 £20 JJ22 j5 r 2 £^ was prepared by the action of bromine on hydro- 

 chlorate of cinchonine. This was treated with alcoholic potash 

 until all bromine was removed, the excess of potash was saturated 

 with carbonic acid, the solution evaporated to dryness, and the 

 salts soluble in water extracted by treatment with water. On 

 treating the residue with boiling alcohol a substance was dis- 

 solved out, which crystallized, on cooling, in colourless laminae. 

 This substance is a base ; its salts crystallize in general with diffi- 

 culty ; its formula is that of quinine, but it is only isomeric with 

 that substance ; its solutions do not become green when treated 

 with hydrochloric e acid and ammonia, nor do they fluoresce like 

 quinine solutions. From analogy with similar substances, this 

 new base may be called oxy cinchonine. 



Wurtz found that when caffeine was treated with potash, 

 methylamine was given off; but he did not investigate the other 

 products of the reaction. Strecker % has examined the decom- 

 position of caffeine by baryta. When heated in a retort connected 

 with a condenser, methylamine and ammonia are given off, and 

 some carbonate of baryta formed. Besides methylamine and 

 ammonia no volatile bodies are formed. The mass in the retort 

 was filtered, supersaturated with sulphuric acid, filtered from the 

 sulphate of baryta, and the filtrate evaporated in the water-bath. 

 On cooling, crystals are formed, the quantity of which increased 

 on the addition of alcohol. These crystals are the sulphate of a 

 new base, which Strecker calls caffeidine. From the analysis of 

 its sulphate, the formula of the base was found to be € 7 H 12 N 4 2 , 

 and its formation from caffeine may be thus expressed : 



€ 8 H 10 N 4 O 2 + H 2 O=€ 7 H i2 N 4 O + CO 2 . 



Caffeine. Caffeidine. 



The occurrence of methylamine and ammonia depends doubtless 

 upon a further decomposition of the caffeine or caffeidine; aud, 

 in fact, Strecker found some other bodies formed which he has 

 not yet investigated. In this transformation, caffeine, in being 

 converted into caffeidine, exchanges GO for H 2 , and that in this 



* Phil. Mag. vol. xvi. p. 138. 



f Liebig's Annalen, September 1862. J Ibid. 



