CONSTITUENTS OF THE BIOSPHERE 



43 



Other steroids not possessing a methyl group arc the C-18 steroids, 

 derivatives of oestrane. The most interesting of these are the oestrogenic 

 hormones in which ring A is a benzene ring (e.g. ©estrone). 



O 



CH3 CHJI 



HO 



Oestrane 



Oestfone 



C. Natural Heterocyclic Compounds 

 (a) Pyrrole Derivatives 



Among the heterocycHc compounds of organic chemistry, those of the 

 pyrrole group present a particular interest to the bicohemist. Pyrrole itself, 

 C4H4NH, has been known for over a century as a product of the dry 

 distillation of organic matter. Its biological importance is very great. 

 Suffice it to say that from indole or phenopyrrole are derived indoxyl and 



H H H 



H— C C-H 



il l| 



H — C C-H 



\ / 

 N 

 H 



Pyrrole 



REFERENCES 



Bergmann, W (1952). Sterols. Progress in the Chemistry of Fats and Other Liquids, 



1 , Pergamon Press, London & New York. 

 FiESER, L. & FiESER, M. (1949). Natural Products Related to Phenanthrene, 3rd 



ed., Reinhold (New York). 

 Heusghem, C. (1950). Metabolisme et analyse des hormones steroides, Masson and 



Desoer, Paris, Liege {Actualites biochimiques. No. 14). 



