TRANSACTIONS OF SECTION B. 731 



10. Oil the Salts of a nevj Flaiimun-sulplmrea Base. By "W. J. Sell, 

 M.A., F.G.S., F.I.C., and T. H. Easterfield, M.A. 



The authors have obtained the salts of a base Pt(CSN„H,)4(OH)2 by the action 

 of platinic chloride upon a hot solution of thiocarbamide in dilute hydrochloric 

 acid, and subsequent addition of the acid the salts of which are required. The 

 chloride Pt(CSN,HJ CL,, sulphate Pt(CSN„Hj)jS04, and the picrate have been pre- 

 pared and analysed. 



The free base corresponding apparently to Eeiset's first base Pt(NH„)4(0H)o 

 has not yet been obtained pure, for its solutions undergo partial decomposition upon 

 evaporation even in a vacuum. That the crystalline residue thus formed contains 

 the base is evident from the fact that the above-mentioned salts can be regenerated 

 from it, 



11. On Cifrazinic Acid. By W. J. Sell, M.A., F.G.8., F.I.C., and 

 T. H. Easterfield, M.A. 



A. W. V. Hofmann has shown that citrazinic acid is in all probability to be re- 

 garded as a, a' dioxyiso-nicotinic acid. In this paper it is shown that in a number 

 of cases the tautomeric keto formula more readily represents the reactions of the 

 substance. The chlorine, bromine, and isonitroso, and derivatives prepared with 

 a view to testing the constitution are quite in accordance with the keto formula, 

 whilst the phenylhydrazo derivative has not been sufBciently studied for the 

 authors to decide its constitution. Isonitroso-citrazinic acid 



CO,H 



HC 

 HOC 



C 

 /"^C : NOH 



CO 



N 



is a somewhat unstable substance, yielding a beautiful silver salt ; when boiled 

 with dilute sulphuric acid it yields quinhydroketopyridin 



CH 



HC/\C0 



HOC 



CO 



N 



which on oxidation with dilute nitric acid yields the corresponding quinone, and by 

 reduction appears to yield the hydroquinone which has not yet been obtained in 

 the analytically pure condition. 



The above-mentioned quinhydroketopyridin dissolves in alkaline solutions with 

 the production of a deep-blue solution, and it appears to be to this cause that the 

 characteristic ' nitrite ' test for citrazinic acid is due. By the oxidation of isonitroso- 

 citrazinic acid with nitric or nitrous acids a bright yellow acid results which gives 

 very characteristic salts. The acid potassium and ammonium salts are precipitated 

 in the crystalline condition by adding the chlorides of these radicles to an aqueous 

 solution of the acid. Although the acid contains only two hydrogen atoms these 

 are both replaceable by metals. Reduction of the yellow acid leads to the formation 

 of the quinhydroketopyridin. 



By the action of cold nitric acid upon citrazinic acid a substance is produced 

 which appears to be represented by the formula 



CH 



NO„cr^\co 



HOC 



N 



CO 



