CHEMISTRY OF THE LEUCOM AINES. "289 



In tin's respect it ns.inlihs hypoxanthine, which, when 

 pure, loi > IK it answer to either of these tests. Another test 

 for adenine, which, however, is given also by hypoxanthine 

 but not by gnanine and catleine, is as follows : The sub- 

 stance to be tested is digested for half an hour with "zinc 

 and hydrochloric acid in a test-tube on the water-bath. If 

 adcnine is present, the solution will assume on standing, 

 more rapidly on shaking, a ruby-red coloration, which later 

 on turns into a brownish-red. This reaction depends upon 

 the formation of a reduction-product, which, owing to its 

 unstable nature, is soon oxidized by the oxygen of the 

 atmosphere into a brownish, amorphous substance, appa- 

 rently identical -with azulmic acid. 



On treatment with nitrous acid, it is converted into hypo- 

 xanthine according to the equation : 



C 5 H 5 N 6 + HN0 2 = C 6 H 4 N 4 + N 2 + H 2 0. 



This formation of hypoxanthine from adenine is analogous 

 to STACKER'S transformation of guanine into xanthine by 

 a similar action of nitrous acid (see Gttanine). In both 

 cases the change of a highly nitrogenized into a less nitro- 

 gen ized body is accomplished by replacing an NH group 

 by O, or, more exactly, of an NH 2 group by OH. In fact, 

 the change is identical with that seen in the conversion 

 of primary amines into primary alcohols. Thus, 



C 2 H 5 .NH 2 + HN0 2 = C 2 H 9 OH -f N 2 +H 2 O. 



ETHTLAMINE. ETHYL ALCOHOL. 



In the extraction of adenine from the mother-liquors of 

 tea-leaves after removal of caffeine, if urea is not added to 

 the nitric acid, nearly one-half of the adenine may be con- 

 verted into hypoxanthine. By processes of putrefaction 

 adenine is converted into hypoxanthine and guanine into 

 xanthine (SCHINDLER). The change is, therefore, some- 

 what analogous to that produced by nitrous acid. Adenine 

 undergoes this decomposition much more rapidly than the 

 other xanthine compounds. 



The ease with which adenine and guanine are reduced 

 outside of the organism shows that similar changes may take 



