332 IV. WAXES, HIGHER ALCOHOLS, ETC. 



of myristic acid do not exhibit the cholesteric phase, but only the smectic 

 modification. In the case of cholesteryl myristate, FriedeP'^^ found that 

 the cholesteric state develops at 72 °C., the smectic phase at 78 °C., and 

 that the compound melts to a clear liquid at 83 °C. Numerous cholesteryl 

 esters have been synthesized, and their properties studied. ^^"^^^^ 



The cholesteryl esters of the fatty acids are quite soluble in boiling 

 ethanol and in boiling acetone. They are only slightly soluble in ethanol 

 at 20 °C., and somewhat more so in acetone at this temperature. ^^^ In the 

 case of the dicarboxylic acids, the monoesters have a considerably greater 

 solubility than do the diesters. 



(3') Chemical Properties of Cholesterol. One of the most important 

 reactions of cholesterol is the ability to form esters, not only with organic 

 acids but also with inorganic acids. In addition to the series of cholesteryl 

 esters the physical properties of which are reviewed in Table 4, a number of 

 non-physiological esters are known. These include the benzoate, C27H45O • 

 OCCeHs, which can be prepared from cholesterol and benzoyl chloride in 

 dry pyridine solution. The plate-like crystals melt at 146.5 °C. to a turbid 

 liquid which clears at 178 °C. On cooling the melted product exhibits a 

 violet fluorescence. Cholesteryl allophanate, C27H45O • OCNHCONH2, re- 

 sults from the action of hydrogen cyanide on cholesterol in benzene solution. 

 This ester is quite difficultly soluble in most solvents. The melting point is 

 recorded as 235-236 °C. by Tange and McCollum,!^^ and as 277-278 °C. by 

 Fabre. '^^ The dicholesterol ester of oxalic acid, C27H45O • OCCO • OC27H46, ''' 

 is sufficiently insoluble to be useful commercially in the separation of 

 cholesterol from other sterols. 



Other cholesterol compounds are those in which this alcohol combines in 

 glucoside linkage with the sugars. Plattner and Uffer^^^ have synthesized 

 glucosides, maltosides, and cellobiosides of cholesterol. When the reaction 

 was carried out in the presence of mercuric acetate or of mercuric acet- 

 amide, a 30 to 50% yield was obtained. It is possible that a combination 

 between cholesterol and glucuronic acid similar to that with the sugars 

 may be the water-soluble form in which cholesterol is excreted in the urine. 

 Although this fraction is ordinarily very small, Bloch and Sobotka^^^ have 

 found it present at ten times the normal level in the urine of cancer patients. 

 Although these workers did not prove the nature of the cholesterol com- 

 pound, they were able to recover the bulk of it only after hydrolysis of the 



180 F. M. Jaeger, Rec. trav. chim., 25, 334-.351 (1906). 



181 P. Gaubert, Comvt. rend., 145, 722-725 (1907). 



182 P. Gaubert, Coinpt. rend., 147, 498-500 (1908). 



183 A. Prins, Z. physik. Chem., 67, 689-723 (1909). 



184 1. H. Page and H. Rudy, Biochem. Z., 220, 304-326 (1930). 



185 U. Tange and E. V. McCollum, /. Biol. Chem., 76, 445-456 (1928). 



186 R. Fabre, Compt. rend., 183, 679-681 (1926). 



187 P. A. Plattner and A. Uffer, Helv. Chim. Acta, 28, 1049-1053 (1945). 



188 E. Bloch and H. Sobotka, /. Biol Chem., 124, 567-572 (1938). 



