NATURAL WAXES 333 



urine. In the case of the closely related sex hormones, it is known that 

 t hese steroids may be secreted as glucuronates or ethereal sulfates. Marx^^* 

 has confirmed the fact that cholesterol occurs in the urine in a water-soluble 

 compoimd, not extractable with fat solvents until after hydrolysis. Bloch 

 and Sobotka'*^ have suggested the possibility that urinary cholesterol might 

 be combined with albumin, although this possibility seems doubtful in view 

 of their finding that clear urine contained as much bound cholesterol as did 

 cloudy samples of urine. In view of the recent report of cholesterol com- 

 jilcxes of protein in blood, which may contain as much as 30% of choles- 

 terol/^" further studies in this field would seem to be advisable. 



In line with the behavior of aliphatic alcohols, cholesterol can readily be 

 transformed to an ether, dicholesteryl ether, which has the formula, 

 C-27H45 • O • C27H45. This ether was first prepared synthetically by Mauthner 

 and Suida,^^^ in 1896, from cholesterol treated with copper sulfate as a 

 dehydrating agent. Other more recent procedures for its preparation have 

 been reviewed by Bills and McDonald. ^^- Silberman and Silberman- 

 Martyncewa^^^ have proved that this compound is a physiological one, 

 since it can be isolated from the spinal cord of cattle in amounts of 1.5 to 

 2.0% of the dry weight. Their product melted at 205-209 °C.; it was 

 soluble in boiling benzene, toluene, and alcohol, slightly soluble in cold benz- 

 ene or toluene, and it dissolved to only a slight extent in cold alcohol, warm 

 ether, or acetone. 



Because of the double bond at the 5:6 position, cholesterol possesses a 

 number of characteristic reactions. Not only will it add hydrogen and the 

 halogens, but it is acted on by perbenzoic acid and ozone. When it is 

 catalytically hydrogenated, dihydrocholesterol (also called j3-cholestanol), 

 C27H47OH, originates. Isomeric compounds result when reduction is 

 brought about by sodium and amyl alcohol. 



Halogens readilj^ react to saturate the cholesterol molecule. One of the 

 best known of these compounds, cholesterol dibromide (C27H45Br20H), 

 originates when cholesterol is treated with an excess of bromine in an ethe- 

 real acetic acid solution. The dibromide crystallizes in characteristic 

 needles which are useful for the detection of cholesterol. They exist in 

 two modifications which melt at 109-111 °C. and 123-124 °C., respectively. 

 Cholesterol dibromide can be reconverted to cholesterol on reduction with 

 sodium amalgam. 



1^^ W. Marx, Personal communication (1950). 



"« I. W. Gofman, F. Lindgren, H. Elliott, W. Mantz, J. Hewitt, B. Strisower, V. Her- 

 ring, and T. P. Lvon, Science, 111, 166-171, 186 (1950). 

 '■'> J. Mauthner and W. Suida, Monalsh., 17, 29-49 (1896). 

 '»= C. E. Bills and F. G. :\IcDonald, ./. Biol. Chem., 72, 1-19 (1927). 

 »" H. Silberman and S. Silberman-Martyncewa, /. Biol. Chem., 159, 603-604 (1945). 



