NATURAL WAXES 323 



these objections to the original Wieland formula were satisfied by the new 

 postulated structure. 



Cholestane has long been recognized as the mother substance of the 

 sterols. The new structure proposed for cholestane was based upon its 

 dehydrogenation to chrysene, which was accomplished by Diels and co- 

 workers^*^- ^'^ when cholesterol or cholic acid was reduced with palladium, 

 charcoal, or selenium. 



Apparently chrysene is produced only when cholesterol or cholic acid is 

 subjected to very energetic dehydrogenation, whereby the original ring D is 

 modified. Ruzicka^*^ and others^*^"^^^ showed that the product, CisHie, 

 obtained by Diels et alJ'^^-^^^ from cholesterol retained the 5-carbon struc- 

 ture for the D ring under certain conditions. The latter compound has 

 frequently been referred to as Diels* hydrocarbon. It is also obtained on 

 dehydrogenation of ergosterol, from the sex hormones, from some of the 



1" O. Diels and W. Gadke, Ber., 58, 1231-1233 (1925). 

 "8 O. Diels, Ber., 66, 487-488, 1122-1127 (1933). 



"' L. Ruzioka, L. Ehmann, M. W. Goldberg, and H. Hosli, Helv. Chirn. Acta, 16, 

 833-841 (1933). 



i« E. Bergmann and H. Ilillemann, Ber., 66, 1302-1306 (1933). 



»" J. W. Cook and C. L. Hewett, /. Soc. Chern. Ind., 52, 451-452, 603 (1933). 



»« O. Diels and H. Klare, Ber., 67, 113-122 (1934). 



'" O. Diels and W. Gadke, Ber., 60, 140-147 (1927). 



»< O. Diels, W. Gadke, and P. Kording, Ann., 4^9, 1-26 (1927). 



