Bell — Farther Observations on Pyrrol and its Derivatives. 173 



The insoluble solid compound formed is filtered off and repeatedly 

 crystallized from boiling spirits of wine, in which it is sparingly 

 soluble in the cold. It then crystallizes in brilliant colourless needles 

 which melt at 90° C, or beneath warm spirit. They are easily de- 

 composed above 100° C. It might have been expected that a body so 

 poor in hydrogen as ethyl-pyrrol would have given an addition com- 

 pound with bromine. But analysis shows that towards this reagent 

 the pyrrol nucleus behaves like benzol. 



Found. Calculated for. 



CBr^NCoHs 

 C = 17-3 17-51 



H = 1-43 

 Br = 77-2 



IS" = — 



1-21 



77-85 



The compound remains apparently unchanged when digested 

 with excess of bromine water. No doubt it has the following consti- 

 tution : — 



Br 

 BrC = a 



I >(C,H,) 

 BrC = (J 

 Br. 



Diethylearhopyrrolamide, CgHul^sO? al^o does not unite directly 

 with, bromine. When bromine dissolved in chloroform is added to a 

 chloroform solution of the amide, it is at once decolourized : but even 

 in the cold, fumes of hydrobromic acid are given off, and, on allowing 

 the chloroform to evaporate, a tenacious mass is left, in all probability 

 a mixture of unchanged amide with a substitution compound. 



"When shaken with bromine water, diethylcarbopyrrolamide yields 

 an insoluble substitution compound and a soluble oxidation product. 

 To obtain the first, careful manipulation is required, since it passes 

 into the second with the greatest ease. The amide is first dissolved 

 by continued agitation in so much warm water that nothing separates 

 on cooling. Bromine water is then dropped in very cautiously, the 

 mixture being shaken after each addition. The two new compounds 

 are produced simultaneously, the first separating in small clots, and 

 rendering the mixture milky. On continuing the addition of bromine, 

 a point is reached at which the milkiness suddenly disappears, and the 

 Kquid becomes transparent, while the clots adhere to the sides of the 

 flask. This clearing marks the point at which all the amide has been 

 acted upon, and any further quantity of bromine added is used up in 

 oxidizing the clots. The liquid is filtered, and the solid residue is 

 repeatedly crystallized from 60^ alcohol, in which it is freely soluble 

 on heating. It separates on cooling, when pure, as a jelly-like mass 

 of long silky needles of extreme tenuity, which require prolonged 

 heating to 100° C. to dry them. The substance is insoluble in water. 



