162 



BIOCHEMICAL SYSTEMATICS 



some of them are of considerable systematic importance. Representa- 

 tive types are illustrated below. 



H 



CH2CH2CH3 



OCH3 



N-^^^O 



ncinin 



nicotine 



anabasin 



/ 

 H2C 



,0 



\ 







CH=CH-CH=CH-CO-N 



piperine 



r~\ 



C0H2C 



1^^ 



N" "CH2CHOH- 



CH3 ^^^ 



lobelin 



CHCH. 



0= 



CH=CH2 



Several minor categories are illustrated below without further com- 

 ment. The term minor is used here strictly to indicate that these 

 groups do not exhibit, in general, the diversity of subtypes encountered 

 among the previous groups. Some of the most important and best 

 known alkaloids will be recognized among this group however. 



Quinolizine derivatives. 



CH2OH 



'N^ 



lupinine 



sparteine 



