174 



PLANT BASES 



[CH. 



Pyridine 



Nn^ 



Pyrrole 



\^ 



Tropane 



n 



V 



Iminazole 



Quinoline 



./N 



L^«> 



Isoquinoline Pyriinidine Iminazole Purine 



1. The pyridine alkaloids. 



These are, as the name implies, derivatives of pyridine. (Pyridine 



is a colourless liquid which boils at 115° C. It is a strong base and forms 



salts with acids.) 



CH 



/\ 

 CH CH 



II I 



CH CH 



\^ 

 N 



Pyridine 



The more important members of this group are: arecoline, coniine, 

 nicotine, piperine and trigonelline. 



Arecoline occurs in the "Betel Nut" which is the fruit of the Areca 

 Palm (Arecha Catechu). 



Coniine occurs in all parts of the Hemlock (Conium maculatum), but 

 more especially in the seed. 



Nicotine occurs in the leaves of the Tobacco plant {Nicotiana 

 Tahacum). It is a colourless oily liquid which is intensely poisonous. 

 Its constitution may be represented as: 



It is readily soluble in water and organic solvents. 



