346 CHEMISTRY OF THE LEUGOMAINS. 



The diuretic action of the purin bodies apparently parallels the 

 effect upon muscles. Thus, paraxanthin is more diuretic than theo- 

 phyllin while theobromin is less effective than the latter. The in- 

 creased reflex irritability, as with ammonia compounds, is due to the 

 nitrogen groups, whereas the action upon muscle is peculiar to the 

 purin molecule. 



Adenin, unlike the other purin bases, has been shown by Minkow- 

 ski to be a violent poison. The profound effects induced, which 

 will be described later, are apparently due to the presence of the 

 amino group. Steudel has also observed a marked toxicity follow- 

 ing the introduction of the amino group into pyrimidin. 



I. The Purin Bases. 



Purin, CjH^N^, was successfully prepared by Fischer* in 1898. 

 It is of interest because it is the prototype of the group to which it 

 lends the name. Although as yet it has not been met with in the 

 body or among the cleavage products of proteids, it is not unlikely 

 but that improved methods will reveal the presence of purin and ite 

 methyl derivatives. A brief description of its properties which 

 clearly place it in the same series with hypoxanthin, xanthin and 

 uric acid, will therefore be appropriate. 



Purin forms colorless microscopic needles often united in spherical 

 aggregates. The melting point is 211-212°. It is very easily sol- 

 uble in cold water and the solutions do not react toward litmus or 

 curcuma. It is also very easily soluble in warm alcohol, from which 

 it slowly crystallizes in small densely felted needles. It is more 

 difficultly soluble in acetic ether and in aceton, and especially so in 

 ether or in chloroform. It forms salts with acids as well as with bases. 



The nitrate, CjH^N^.HNOj , is very easily soluble in hot water ; 

 rather difficultly so in hot alcohol. It crystallizes in roundish 

 aggregates. On warming with dilute nitric acid it becomes yellow. 

 It melts at 205° with decomposition. The chlorid, iodid and sul- 

 phate are extremely soluble in water. 



The picrate is difficultly soluble, requiring about twenty parts of 

 boiling water. It forms yellow glistening needles which melt at 208°. 



The platinochlorid forms, upon the addition of platinum chlorid 

 to fairly concentrated solutions of the chlorid, as fine yellow needles 

 which readily dissolve on heating. Gold chlorid gives an oily or 

 resinous precipitate, which in time forms a solid yellow, granular 

 mass which is also readily soluble on heating. 



The sodium salt is very soluble in water, difficultly so in concen- 

 trated sodium hydrate from which it crystallizes in bundles of fine 

 needles. The potassium and barium salts are likewise very soluble. 



^Berickte, 31, 2550; 32, 493. 



