22 THE SIMPLER NATURAL BASES 



most convenient method for obtaining the base in quantity ; 7-amino- 

 butyrylacetal is heated with phenyl-hydrazine and zinc chloride. 



CH, . CH 3 . CH 2 . NHj 

 ;'NH . NH 3 CH (OC a H e ) 2 



C . CH 2 . CH a . NHj 



CH + NH, + 2C 2 H 5 OH 



NH 



From the concentrated solution of the crude hydrochloride (obtained 

 by washing the reaction mixture with ether and removing the zinc as 

 sulphide) the free base is precipitated by sodium hydroxide as an oil, 

 which on keeping crystallises to a mass of fine needles. 



Laidlaw [1911] dissolved o - 5 grm. tryptophane in 250 c.c. of tap 

 water, together with 0*5 grm. peptone, 2 grm. glucose, traces of sodium 

 phosphate and magnesium sulphate and added 5 grm. of calcium car- 

 bonate ; this is the culture medium employed by Ackermann in the 

 decarboxylation of histidine (p. 132). After infection with a subculture 

 from putrid pancreas and incubation for a fortnight the mixture was 

 boiled with charcoal and concentrated. Picric acid then precipitated 

 the deep orange red picrate of indolethylamine. Yield after purifica- 

 tion = 0-14 grm. = 14 per cent, of the theoretical. 



The decarboxylation of tryptophane cannot be effected by heat. 

 The author's experiments in this direction were carried out under a 

 pressure of I mm. ; the only substance which could be isolated from 

 the sublimate was a small quantity of unchanged tryptophane. 



/Mminazolyl-ethylamine, C 5 H 9 N 3 . 



yS-Iminazolyl-ethylamine (4-/3-amino-ethyl-glyoxaline) is the amine 

 derived from histidine by decarboxylation ; it is of considerable in- 

 terest on account of its great physiological activity. The base was 

 first obtained by Windaus and Vogt [1907] who prepared it by 

 Curtius's method from iminazolyl-propionic acid, which can be 

 made by synthesis as well as from histidine. A few years later 

 Ackermann [1910, l] submitted pure histidine hydrochloride to the 

 action of putrefactive bacteria and obtained a relatively large yield of 

 iminazolyl-ethylamine (together with a small quantity of iminazolyl- 

 propionic acid). The physiological activity of the amine, however, 

 remained unknown until the latter was identified as one of the active 

 principles of ergot by Barger and Dale [1910, 2-4]. The same active 

 principle was simultaneously isolated from ergot by Kutscher [1910, l] 

 who at first regarded it as closely related to iminazolyl-ethylamine, but 



