Bell — Further Observations on Pyrrol and its Derivatives. 171 



and di-carboxyl derivatives of these pyrrols. The corresponding acid& 

 had not at that time been procured. These amides are rather stable 

 compounds, and are very sloTvly attacked by mineral acids and alkalis. 

 If it is attempted to decompose them by prolonged boiling "with 

 strong alkaline solutions, it is impossible to prevent the decomposition 

 of the acids as fast as formed. I have found, hovrever, that they may 

 be easily split up by enclosing them in sealed tubes "with strong alco- 

 holic potash, and exposing the tubes for some time to a temperature 

 of about 120°C. They are then resolved with facility into free am- 

 monia-base and the potash salts of the corresponding acids ; thus — 



Dimethyl-carbopviTolamide. Methyl-carbopyrrolic acid. 



C4H3N(CH3)(CONHCH3) + KHO = CiH:3^XCH3)COOK + NH.CHa. 



Dietliyl-carbopyrrolainide. Ethyl-carbopyirolic acid. 



C4H3]S^(aH5)C0Is^HCoH5 + XHO = C4H3N(C3H5)C00K + NHoCoHs- 



I have not, however, been able to obtain amyl-carbopyrrolic acid. 

 Its amide when heated with potash yields amyl pyrrol, amylamine, 

 and potassic carbonate. 



CHsXCCsHiOCOKSCsHn + 2KH0 = CiHiy(CaH„) + KoCOg + 



The potassium salts of these acids are obtained in the solid form 

 by evaporating their alcoholic solutions. They are very soluble in 

 water and alcohol. By cautiously adding to their concentrated aqueous 

 solutions dilute hydi'ochloric acid in very sliylit excess, the mixtiu-e 

 being carefully cooled from time to time, the acids are separated as 

 flocculent precipitates which soon become crystalline. The crystals 

 must be rapidly washed with cold water. To remove small quantities 

 of silica (derived from the glass tubes) they must be dissolved in am- 

 monia and again precipitated with hydrochloric acid. When thoroughly 

 free from mineral acid they may be crystallized from water at about 

 90°C. (not higher), in which they are freely soluble. 



Methylcarlo2>yrrolic acid crystallizes in needles which are very so- 

 luble in alcohol and ether. It melts at 135°C. ; heated a little beyond 

 this point, it breaks up into methyl-pyrrol and carbonic anhydride. 



C4H3iS^(CH3)COOH = CiH4jS'(CH3) + CO.. 



It volatilizes with partial decomposition in a current of steam. Its 

 salts are as a rule easily soluble in water : those of the alkalis and 

 alkaline earths dissolve in alcohol. Argentic methyl-carhopyrrolate C4II5 

 !N'(CIl3)C00Ag, obtained by double decomposition, crystallizes from 

 much boiling water in transparent prisms which deflagrate feebly when 

 heated. '446 grams of the finely powdered salt, mixed with sand to 

 avoid loss by too rapid decomposition, gave on cautious ignition '206 

 grams of silver = 46-19 per cent. ; calculated = 46-55 per cent. 



Ethylcarhopyrrolic acid, similarly prepared, bears a great resem- 

 blance to the methylated acid. It is, however, rather less stable, more 

 soluble in water, and melts at 78°C. The silver salt is much more 



