HYPOXANTHIN. 375 



Even caffein, which resembles dimethyl hypoxanthin, does not enter 

 into such a combination. 



The free base is obtained by treatment of this compound with 

 freshly precipitated silver oxid. It melts at 244°- 246° (Fischer). 

 From chloroform it crystallizes in fine silky needles, containing three 

 molecules of water of crystallization. From alcohol it crystallizes in 

 groups of small pointed anhydrous crystals. It is easily soluble in 

 water and chloroform ; less so in alcohol. A strong solution of the 

 base reacts with silver nitrate, with nitric acid and silver nitrate, 

 with copper sulphate and sodium bisulphite (in the cold, not on 

 warming). Copper sulphate and sodium thiosulphate do not give a 

 precipitate. A one per cent, solution of the base gives precipitates 

 with mercuric chlorid, platinum chlorid, and gold chlorid, but not 

 with lead acetate, basic lead acetate, picric acid, and ammoniacal 

 silver solution. 



On account of the solubility of this base in water and chloroform ; 

 the fact that it is not precipitated by ammoniacal silver solution, 

 which precipitates all bases of the uric acid group containing a re- 

 placeable imido group ; also on account of its behavior with copper 

 sulphate and mercuric chlorid, Kriiger concluded that hypoxanthin 

 contained only two imido groups capable of substitution. In addi- 

 tion to these adenin contains a third amido group, which is not re- 

 • placeable, and which with nitrous acid is replaced by oxygen. The 

 nitrogen in position 9, however, is capable of forming methyl com- 

 pounds. 



On decomposition with concentrated hydrochloric acid at 180°— 

 200° it yields one molecule of methylamin and two of ammonia 

 and one of sarkosin, according to the equation : 



C.H.(CH3),Np + 7H,0 = 2NH3 + CH3NH, -f- COj + 

 2HC00H + CH3.NH.CH,.COOH. 



The isomer 1-9-di-methyl hypoxanthin is probably formed from 

 9-methyl hypoxanthin (Fischer). 



Diethyl hypoxanthin ethyl iodid, C5H,(C3H5),Np.C2H5l. This 

 compound was also prepared by Kruger, by heating hypoxanthin- 

 lead with ethyl iodid. It crystallizes from alcohol in beautiful four- 

 sided glistening prisms, which are easily soluble in water and in hot 

 alcohol ; insoluble in ether. 



Iso-amyl hypoxanthin, Q^J^Q^^^TSf), was likewise prepared 

 by Kriiger by heating hypoxanthin in the presence of sodium hy- 

 drate and alcohol with amyl iodid. It forms six-sided rhombic 

 plates and is easily soluble in chloroform, difficultly in cold water, 

 insoluble in ether. 



Di-iso-amyl hypoxanthin, C^J(^Jdi^^^ p, is formed in small 

 amount at the same time as the preceding. It yields a hydrochlo- 

 rid crystallizing in small needles. The base is set free from solu- 



