162 



TERPENOIDS AND STEROIDS 



CO OH 



Oleanolic Acid 



CH3 



1, 8-Dimethylpicene 



Stigmasterol 



Diel's Hydrocarbon 



Paper chromatography of the higher terpenoids and steroids has generally been 

 unsuccessful by normal methods because of the non-polar nature of most of these com- 

 pounds. Reversed phase chromatography has been used most widely. The paper is im- 

 pregnated with such stationary phases as aluminum oxide, mineral oil, or aluminum 

 soap, and non-polar, mobile phases used for development. Generally only rather non- 

 specific spray reagents are available for detection of the terpenoids and steroids. One 

 of the commonest is 10% antimony trichloride or pentachloride in chloroform, followed 

 by heat. Table 14 summarizes some of the literature on paper chromatography of ter- 

 penoids and steroids. 



Thin layer chromatography has also been usefully applied to the steroids and higher 

 terpenoids. Silica gel is the commonly used adsorbent and analyses have been made of 

 cardiac glycosides (80), triterpenoids (81), carotenoids (82), and benzoquinones (83). 

 Gas chromatography can also be applied even to the rather non-volatile steroids and 

 triterpenoids (84). 



Many color reactions of the higher terpenoids and steroids have been recorded in 

 the literature, and some of them could probably be adapted for use on paper chromato- 

 grams. One of the best known is the Liebermann-Burchard reaction on giving a blue- 

 green color with most sterols and triterpene alcohols when they are mixed with ace*^'" 



