HYPOXANTHIN. 373 



glittering crystals which have the composition CjH^N^O.HgClj 



The following table of Bruhns illustrates the analogy existing 

 between the mercury compounds of adenin and hypoxanthin and 

 similar derivatives of ammonium : 



Ammonium. Adenin. Hypoxanthin. 



NH,HgCl CsHAHgCl C5H3N40Hga( + H,0) 



NH,Hg,Cl, CsH.NsHIcI, C5H,N,0Hg,Cl,( + H,0) 



(NH3),HgCl,{ i§igf)|S|f2^^^^(N0,),0H C,H,N,OHgCl,( + H,0) 



Hypoxanthin, as well as guanin and xanthin, forms readily soluble 

 compounds with fixed alkalis. From these solutions the alkali com- 

 pounds tend to crystallize on gradual evaporation, in rosettes or 

 bundles of needles — difference from heteroxanthin and paraxanthin 

 (Salomon). The alkali solutions of the xanthin bases are precipi- 

 tated by carbonic acid and behave with acid salts, bicarbonates, and 

 ammonium salts the same as the heteroxanthin-sodium compound. 



According to Bruhns, hypoxanthin and uric acid are unalfected by 

 the action of dry bromin, even at 100°, but Kriiger has shown this 

 statement to be incorrect. Bromin has no action on hypoxanthin at 

 ordinary temperatures, but at 100° and as high as 150° the latter is 

 changed quantitatively into brom-hypoxanthin. A dark-red crys- 

 talline mass is obtained which contains six atoms of bromin to one 

 molecule of hypoxanthin. It is a tetra-bromid of brom-hypoxanthin 

 hydrobromid, CjHjBrN^O.HBr.Br^ , analogous to the similar com- 

 pound of adenin. It loses bromin slowly in the cold, rapidly at 120°, 

 and brom-hypoxanthin hydrobromid remains, CjHjBrN^O.HBr. 

 From this salt the free base can be obtained after conversion into 

 the sodium compound. For this purpose the solution of the salt is 

 treated with sodium hydrate or carbonic acid, or saturated direct 

 with sodium carbonate, then concentrated to crystallization. 



Brom-hypoxanthin, CjHjBrN^O -|- 2HjO. This can be prepared 

 as just described, or by the action of nitrous acid on brom-adenin at 

 70°. It forms a heavy powder of small, coarse crystals ; may form 

 spherical groups of long, hair-like needles containing 1| molecules 

 of water. It is difficultly soluble in water ; easily soluble in acids 

 and alkalis. The aqueous solution reacts strongly acid. It has the 

 properties of a base and an acid, behaving with alkalis and alkali 

 carbonates the same as uric acid, setting free carbonic acid from the 

 latter. 



An aqueous solution of brom-hypoxanthin reacts with silver 

 nitrate, ammoniacal silver solution, mercuric chlorid, copper sul- 

 phate, and sodium bisulphite. In acid solution it is precipitated 

 by tannic acid, phosphotungstic acid, phosphomolybdic acid, by basic 

 lead acetate ; and is not precipitated by lead acetate or by baryta 

 water. 



