APPENDIX TO CHAPTER I AMINES 131 



is the most useful and characteristic derivative of the base. Formed 

 by the Schotten-Baumann reaction, it crystallises readily from alcohol 

 and melts at 170; this derivative gives Morner's reaction, but not 

 Millon's. 



Yeast transforms p-hydroxy-phenyl-ethylamine to the correspond- 

 ing alcohol, tyrosol, OH . C H 4 . CH 2 . CH 2 OH (Ehrlich and 

 Pistschimuka [1912]). p-Hydroxy-phenyl-ethylamine is attacked by 

 various oxidases and converted to pigments, but does not always 

 behave in the same way as its parent substance tyrosine. Thus 

 Neuberg [1908, Ch. VI] found that a ferment from a melanoma at- 

 tacked the amine, but not the amino-acid, whereas an extract of the 

 ink-bag of Sepia acts on tyrosine more readily than on the amine. 

 Compare also J. Chem. Soc., Abstr., 1908, 94, i., 236. 



Hordenine. 



Gaebel's process of isolation was as follows : The extract of 3 kilos, 

 of malt germs with 95 per cent, alcohol was evaporated to a syrup 

 and extracted with I litre of water. After filtration the aqueous 

 extract was made alkaline with sodium carbonate, shaken once with 

 a little ether to remove a colouring matter, and then ten times with 

 large quantities of ether. The concentrated ethereal extract was 

 dried with potassium carbonate and evaporated, when the residual 

 syrup soon crystallised. On recrystallisation from dry ether, with 

 charcoal, the pure base is obtained; the yield is 0*2 per cent, of the 

 air dry germs. 



Properties. 'Hordenine forms colourless crystals melting at II7'8 

 (corr.) and boiling at 1 73-1 74" and 1 1 mm. Distillation under reduced 

 pressure is the most convenient method of purification. The base 

 dissolves readily in alcohol and in chloroform, and fairly readily in 

 ether and in water ; it is hardly soluble in benzene. Hordenine gives 

 Millon's and Piria's reactions for tyrosine, and reddens phenolphtha- 

 lein ; it is not coloured by concentrated sulphuric acid, but reduces 

 potassium permanganate in the cold and ammoniacal silver nitrate on 

 warming. 



The sulphate, (C 10 H 15 NO).j. H 2 SO 4 . H 2 O, the hydrochloride and the 

 hydrobromide are sparingly soluble in alcohol. The quaternary iodide, 

 hordenine methiodide, obtained by the action of methyl iodide in 

 methyl alcoholic solution on hordenine (or on p-hydroxy-phenyl-ethyl- 

 amine), forms large glassy prisms, sparingly soluble in cold water ; 

 m.p. 230-231. 



9* 



