ADENIN. 361 



adenin compound. Prolonged boiling with nitric acid results in the 

 separation of silver bromid. Mercuric chlorid, cadmium chlorid, 

 potassium bismuth iodid, etc., give precipitates with brom-adenin 

 the same as with adenin. 



Brom-adenin gives the xanthin reaction, whereas adenin itself 

 does not. Thus, if evaporated with strong nitric acid on the water- 

 bath to dryness, and the cold yellowish or reddish residue is touched 

 with sodium hydrate, a bluish-violet color forms. With ammonia it 

 is a purple-red ; with baryta water a pure violet. 



Dry chlorin gas passed over warm dry brom-adenin has no effect. 

 If, however, the brom-adenin is moist, decomposition and solution 

 result. On evaporation of the solution the residue gives with potas- 

 sium hydrate an intense violet-red color ; baryta produces a bluish- 

 green precipitate. 



It is therefore evident from the above reactions with nitric acid 

 and chlorin that brom-adenin is more readily destroyed or oxidized 

 than adenin. Inasmuch as all attempts at obtaining oxidation 

 products of adenin which would shed light on its constitution failed, 

 the study of the oxidation products of brom-adenin therefore pos- 

 sessed special interest. Kriiger succeeded in oxidizing brom-adenin 

 with hydrochloric acid and potassium chlorate in warm solution, 

 into alloxan, urea, and oxalic acid. A reddish substance which 

 dissolved in alkalis with a purple-red color was also produced in 

 small amounts. Its alkaline solution gave a dirty-blue precipitate 

 with baryta. The amount of alloxan found was very small ; indeed, 

 in one experiment it was entirely absent. Nevertheless, it was 

 sufficient to prove that in adenin, and hence in hypoxanthin, an 

 alloxan group and probably an urea residue were present as in uric 

 acid and xanthin. 



When adenin is treated vrith zinc and hydrochloric acid in the 

 cold it forms a difficultly soluble crystalline double salt which has 

 not been obtained in the pure state. This double salt is not obtained 

 by direct treatment of adenin hydrochlorid with zinc chlorid. 



One of the hydrogen atoms of adenin is capable of replacement 

 by organic radicals, as seen from the following compounds : 



Acetyl adenin, CjH^Nj.CO.CHj, can be obtained by heating the 

 anhydrous base with an excess of acetic anhydrid for some time, in 

 an oil-bath, at 130°. It crystallizes in small white scales which 

 dissolve but slightly in cold water and in alcohol ; more readily in 

 hot water, in dilute acids and alkalis. Heated to 260°[it becomes 

 yellow, but does not melt. 



Benzoyl adenin, CjH^Nj .CO.C5II5 , is obtained by the action of 

 benzoic anhydrid, but not of benzoyl chlorid or adenin. It crystal- 

 lizes from water in long, lustrous, thin needles which sometimes are 

 grouped in bundles and melt at 234°— 235°. It is easily soluble in 

 hot alcohol, from which it recrystallizes on cooling ; also in dilute 



