378 Mr. P. Griess on a New Class of Compounds [June 16, 



Biazobenzol, Gg Ng. 



This substance is obtained when an aqueous solution of the compound 

 of hydrate of potassium with diazobenzol is neutrahzed with acetic acid. 

 It separates as a thick yellow oil of very little stability. After a few 

 moments an evolution of gas ensues, and the diazobenzol is rapidly con- 

 verted into a reddish-brown viscid mass. Diazobenzol is soluble in acids, as 

 well as bases, with formation of the saline compounds previously described. 



By acting in the cold with aniline upon nitrate of diazobenzol*, the 

 following change takes place : — 



H, N, NH O3 + 2€, H, N= H,, N3 + H, N , NH03^ 



Nitrate of diazo- Aniline. Diazoamido- Nitrate of aniline, 

 benzol. benzol. 



I was formerly of opinion that diazoamidobenzol must be viewed as a 

 double compound of diazobenzol and aniline. The above equation seems 

 to confirm this view. 



New compounds analogous to diazobenzol-amidobenzol are obtained by 

 the action of other organic bases upon nitrate of diazobenzol, viz. diazo- 



benzol-amidobromobenzol, | g N J ' action of bromaniline. 



Naphthalidine and nitrate of diazobenzol combine directly and form nitrate 

 of diazobenzol- amidonaphtol, crystallizing in magnificent large green prisms. 



The action of amido-acids upon nitrate of diazobenzol is analogous to 

 that of the aniline ; ex. gr.y 



OgH.N,, NH034-2G,H,NO,= {^^g^^^ } +aH,NO„NH03. 



Nitrate of diazo- Amido-acid. Diazobenzol- Nitrate of amido- 



benzol. arnidobenzoic acid. benzoic acid. 



Diazobenzol-amidobenzoic acid separated quickly as a yellow crystalline 

 mass on mixing the aqueous solutions of both substances. It is purified 

 by recrystallization from ether in the form of small yellow plates. It 

 combines with bases and forms saline bodies. Bichloride of platinum 

 precipitates from an alcoholic solution a yellowish-white crystalline pla- 

 tinum-salt of the composition €^3 H^^ Ng O^, 2IIC1, 2PtCl2. 



Similar double acids to the one just described are obtained by the action 

 of amidodracyhc acid, amidoanic acid, &c., upon nitrate of diazobenzol. 



Imidogen Compounds of Diazohenzol. 

 These peculiar compounds are formed when aqueous ammonia, as well as 

 certain organic bases, are made to act upon the dibromide of diazobenzol. 



* It is self-evident that for this and similar experiments sulphate and hydrobromate of 

 diazobenzol may also be employed. 



