NATURAL WAXES 



355 



most sterols at tho 5,6 position is absent. A second natural sterol, zymo- 

 sterol, is also saturated at the 5,6 position. 



The a-spinasterol has also been shown to be a component of alfalfa seed 

 QJI283,284 {Medicago sativa), as well as of seneca snake-root^*^^ (Polygala 

 senega). In all probability, the medicap;osterol 11 isolated by Dam et al.-^^ 

 from alfalfa extracts is a-spinasterol. 



e'. Campesterol: Campesterol is a mono-unsatiirated sterol isolated by 

 Fernholz and MacPhillamy-*^ from rapeseed (Brassica campestris) . It 

 melts at 157-158 °C., and it has a specific rotation of —33°. It belongs to 

 the C28 series and is believed by Fernholz and Riiigh-'*^ to have the follow- 

 ing structure in which an asymmetiy around C24 is evident: 



CH, 

 H I 

 CH-CH = CHC-CH-CHs 



I 

 CH5 



. Campesterol 



f. Dihydrositosterol : Dihydrositosterol, C29H51OH, has been reported 

 in a number of oils, including corn, wheat, rice, and rye, as well as in the 

 so-called tall oil, which is a by-product of the paper manufacturing indus- 

 try. This sterol forms colorless platelets which melt at 144 °C. and which 

 have a specific rotation of 28.0° at 18 °C. The acetate, C29H51O • OCCH3, 

 melts at 141 °C. and has an [a]^ of -1-12.72°. Because of the absence of 

 any unsaturated linkage, dihydrositosterol does not respond to the Lieber- 

 mann-Burchard or Salkowski tests for the sterols. 



(/) Occurrence and Properties of Mycosterols. The sterols elaborated by 

 the cryptogams differ markedly from those found in higher plants or ani- 

 mals, although the essential characteristics of the sterol nucleus are re- 

 tained. Because of its widespread distribution, as well as because it is a 

 precursor of vitamin D, ergosterol assumes the most importance in this 

 group. Two other members, fucosterol and zymosterol, are also well knouTi. 



a'. Ergosterol: Tanret-*'* isolated ergosterol from the fungus ergot 



»3 L. C. King and C. D. Ball, /. Am. Chem. Soc, 61, 2910-2912 (1939). 



^* E. Fernholz and M. L. Moore, J. Am. Chem. Soc, 61, 2467-2468 (1939). 



2«5 H. Dam, A. Geiger, J. Glavind, P. Karrer, W. Karrer, E. Rothschild, and H. Salo- 

 mon, Helv. Chim. Ada., 22, 310-313 (1939). 



«« E. Fernholz and H. B. MacPhillamy, /. Am. Chem. Soc, 63, 1155-1156 (1941). 



=«' E. Fernholz and W. L. Ruigh, /. Am. Chem. Soc, 63, 1157-1159 (1941). 



=»8 C. Tanret, Ann. chim. phijs. [5], 17, 493-512 (1879). Cited by C. E. Bills, Physiol. 

 Revs., 15, 1-97 (19:35). 



