CLASSIFICATION 265 



From these formulae it may be seen that coniine is derived 

 from pyridine, or more strictly from piperidine 



CH, 



CH a CH a 

 CH a CH, 



HN 



Piperidine 



whilst nicotine contains two rings, one a pyridine ring and 

 the other a pyrrolidine ring 



,-CH, 



, CH a 



Pyrrolidine 



such as is also found in proline (see p. 325). 



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

 prising as yet only three alkaloids, namely : 



Hygrine and Kuskhygrine, from the leaves of Erythroxylon 



Coca, and 

 Stachydrine, from the tubers of Stachys tuberifera* and 



leaves of Citrus vulgar is. \ 

 The constitution of stachydrine is as follows : 



co c 



CH a CH 2 



CH 



N(C1 



[(CH 8 ) 2 

 Stachydrine 



showing it to be a dimethyl betaine of pyrrolidine. 



III. Tropane Alkaloids. The alkaloids belonging to this 

 group are derivatives of tropane 



CH 2 



CH 



CH CH 



H 2 CH a 



Tropane 



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

 Gesells.,".i8g3, 26, 939 ; Schulze and Trier : id., 1909, 42, 4654 ; " Zeit. physiol. 

 Chem.," 1910, 67, 59- 



fjahns: "Ber. deut. chem. Gesells.," 1896, 29,2065. 



