352 CHEMISTRY OF THE LEUCOMAINS. 



completely decomposed, with formation of carbonic acid and 

 ammonia : 



C5H5N5 + 5H,0 + SO = 5C0, + 5NH3. 



When heated with 20 per cent, sulphuric acid in an autoclave at 

 150° for two hours adenin is decomposed (Jones). 



On heating adenin with concentrated hydrochloric acid to 180°- 

 200° for 12-14 hours, Kriiger obtained ammonia, carbon dioxid, 

 carbon monoxid, and glycocoll. The carbon monoxid results from 

 the splitting up of formic acid. This decomposition is strictly 

 analogous to that of hypoxanthin, xanthin, etc. 



C5H5N5 + 8H,0 = 4NH, + CO, + 2CH,0, + CjH^NOj. 



The free base, as well as benzoyl adenin, is unaffected by the weak 

 oxidizing action of potassium permanganate, but on stronger oxida- 

 tion it is wholly destroyed. Bromin water produces in aqueous 

 solutions of adenin an oily precipitate which, on contact with potas- 

 sium hydrate or ammonia, gives a beautiful red or violet color. 

 Sodium amalgam and zinc chlorid appear to have no action ; but on 

 boiling with zinc and hydrochloric acid it yields a very unstable 

 reduction product which, in the presence of oxygen, in alkaline 

 solution, first assumes a red color and finally throws down a reddish- 

 brown precipitate. This brown substance appears to be identical 

 with azulmic acid, which has been known for a long time as a product 

 of the polymerization of hydrocyanic acid. 



Adenin and hypoxanthin do not give the xanthin reaction ; that is 

 to say, when adenin is evaporated on a water-bath with dilute or 

 fuming nitric acid it gives a white residue which fails to give any 

 coloration with sodium, ammonium, or barium hydrate (xanthin 

 reaction). Similarly, it does not give the so-called Weidel's reaction 

 on heating with fresh chlorin water and a trace of nitric acid as long 

 as gas is given off, then evaporating to dryness on a water-bath and 

 exposure of the residue to an ammoniacal atmosphere. In this re- 

 spect it resembles hypoxanthin which, when pure, does not answer 

 to either of these tests. When either of these bases, however, is 

 evaporated on a water-bath with bromin water and nitric acid a 

 residue is obtained which with alkalis is colored red (Kossel). An- 

 other tfist for adenin, which is given also by hypoxanthin, but not by 

 guanin, caffein, and episarkin, is as follows : The substance to be 

 tested is digested for half an hour with zinc and hydrochloric acid 

 in a test-tube on a water-bath. If adenin is present, the solution 

 will assume on standing, more rapidly on shaking, a ruby-red colora- 

 tion which in time disappears. The colorless liquid on dilution and 

 addition of sodium hydrate becomes again red, which later on turns 

 into a brownish-red (Kossel). This reaction depends upon the for- 

 mation of a reduction product which, owing to its unstable nature, 



