362 NITROGEN BASES 



Trigonellin from Trigonellum fceniim, Pisum sativum, etc. 



Piperine from Piper, and 



Nicotine from Nicotiana tabacum. 



Some idea of the structure of the molecules of alkaloids 

 belonging to this group may be obtained from the two following 

 constitutional formulae, which represent coniine and nicotine 

 respectively : — 



From these formulae it may be seen that coniine is derived 

 from pyridine or more strictly from piperidine — 



CH, 



CHj CHj 



I I 



CHg CHg 



\ / 

 HN 



Piperidine 



whilst nicotine contains two rings, one a pyridine ring and 

 the other a pyrrolidine ring — 



CH, CH, 



CHg CHg 



NH 

 Pyrrolidine 



such as is also found in proline (see p. 444). 



II. Pyrrolidine Alkaloids. — This is a small group, com- 

 prising as yet only three alkaloids, namely : — 



Hygrine and Kushygrine, from the leaves of Erythroxylon 



Coca, and 

 Stachydrine, from the tubers of Stachys tuberifera * and 

 leaves of Citrus vulgaris.-]- 



* Planta and Schulze : " Arch. d. Pharm.," 1893, 305 ; " Ber. deut. 

 chem. Gesells.," 1893, 26, 939. Schulze and Trier: id., 1909, 42, 4654; 

 " Zeit. physiol. Chem.," 1910, 67, 59. 



t Jahns : " Ber. deut. chem. Gesells.," 1896, 29, 2065. 



