354 



IV. WAXES, HIGHER ALCOHOLS, ETC. 



ascribed the configuration, 5,6,22,23-ergostadienol to it. 22-Dih3^dro- 

 brassicasterol is believed to be isomeric with campesterol, the only differ- 

 ence between the molecules being the isomerism on C24. 



The unsaturated linkages of brassicasterol are readily saturated with 

 bromine. Like most of the other sterols isolated from natural sources, it 

 also is readily precipitated with digitonin. The sterol crystallizes from 

 alcohol in glistening hexagonal platelets which contain one molecule of 

 water of crystallization. It melts at 148 °C. and has a specific rotation of 

 -64.5° in chloroform at 18°C. 



Brassicasteryl acetate, C28H45O • OCCHa, forms hexagonal platelets when 

 crystallized from ethanol. It melts at 157-158 °C. The benzoate ester, 

 C28H450-OCC6H5, when prepared from ethanol, forms long silk-like needles 

 which are especially characteristic. They melt at 167 °C. to a turbid liquid 

 which clears at 169-170 °C. This assumes a blue-green color on cooling. 



d'. Spinasterol: Spinasterol is the name of a series of phytosterols 

 which are closely related to the 7-sitosterols and which are isomeric with 

 stigmasterol. Larsen and Heyr-^"'"** isolated three isomers from spinach 

 fat which were designated as a, /S, and 7. On hydrogenation, the three 

 forms all yield spinastanol, which is identical with stigmastanol.-^^ Fern- 

 holz and Ruigh^^o first postulated that a-spinasterol is 8,14,22,23-stig- 

 mastadienol. Subsequent experimental evidence'**^ based upon its oxida- 

 tion products seemed to indicate that the cyclic double bond is located at 

 position 8,9 instead of at 8,14 but Barton '-^^ more recently proved that it is 

 located in the 7,8 position. In view of the fact that the sterol has a low 



CH3 



CH 



I 2 



CH-CH=CH-C-CH-CH3 



I I ^ 



H CH, 



a-Spiuasterol 



levo rotation, and since a-spinastadienone is not an a:,)8-unsaturated ketone, 

 Simpson-^2 j^^j^g suggested that the usual unsaturated linkage present in 



2" F. W. Hey] and D. Larsen, J. Am. Chem. Soc, 56, 942-943 (1934). 



278 D. Larsen and F. W. Heyl, /. Am. Chem. Soc, 56, 2663-2665 (1934). 



279 C. D. Larsen, /. Am. Chem. Soc, 60, 2431-2434 (1938). 



2s« E. Fernholz and W. L. Ruigh, ./. Am. Chem. Soc, 62, 2341-2343 (1940). 



2" H. E. Stavely and G. N. Bollenback, ./. Am. Chem. Soc, 65, 1600-1603 (1943). 



282 J. C. E. Simpson, /. Chem. Soc, 1937, 730-733. 



