346 



IV. WAXES, HIGHER ALCOHOLS, ETC. 



e'. Ostreasterol : Another type of zoosterol was first prepared by 

 Bergmann^^'* from the non-saponifiable matter of oysters {Ostrea virginica), 

 and of the clam {Venus mercenaria) . Apparently, this is the only sterol 

 present in the oyster; it is possible that it replaces cholesterol in all species 

 of the Lamellihranchiata. It occupies a position midway between the 

 zoosterols and the phytosterols. Ostreasterol melts at 143 °C. and, like 

 cholesterol, it has a specific rotation which is on the levo side ( — 43.6°). 

 Although Bergmann'^* originally believed that ostreasterol belonged to the 

 C29 series, this conception now seems incorrect and the formula C28H45OH 

 has been suggested. ^''^ Bergmann and Low^^-"' consider that it is probably 

 identical with chalinasterol. 



f. Chalinasterol: Bergmann and collaborators ^^^ have isolated a sterol 

 from the sponges (Chalina arbuscula Verrill and Tetilla laminaris Wilson) 

 which melts at ]44°C. and has a specific rotation of —42°, When it is 

 hydrogenated, it is converted into campesterol. It is therefore identified 

 as the 24a-epimer of brassicasterol. 



CH, 



CH, 



I 



CH-CH=CHC-CH-CH, 

 H I ' 



Chalinasterol 



g'. Isocholesterol : Schulze^^^^^^" called the cholesterol-like material 

 present in lanolin or wool grease "isocholesterol." This was later shown to 

 consist of at least two substances, ^^^ which are now referred to as agnosterol 

 and lanosterol. Agnosterol has the empirical structure C30H47OH (m.p., 

 162°C., [all, = +70.6°), while lanosterol has the composition C30H49OH 

 (m.p., 141 °C., [q:]d — +58°). Agnosterol has three unsaturated linkages, 

 whereas lanosterol possesses only two double bonds. Windaus and 

 Tschesche^*^ obtained 50 grams of isocholesterol from 1 kilogram of lanolin ; 

 this isocholesterol contained 4 grams of agnosterol and 45 grams of lano- 

 sterol. These were readily separated from each other by fractional crystal- 

 lization of the acetates from diethyl ether. Agnosteryl acetate is only 

 slightly soluble in this solvent, while lanosteryl acetate is extremely so. 



Neither of these compounds is isomeric with cholesterol; in fact, it is now 



228 E. Schulze, Ber., 5, 1075-1078 (1872). 



"^ E. Schulze, Ber., 6, 251-254 (1873). 



"0 E. Schulze, J. prakt. Chem., N, S. 7, 163-178 (1873). 



"1 A. Wmdaus and R. Tschesche, Z. phijsiol. Chem., 190, 51-61 (1930). 



