THE CHEMISTRY OF CHOLESTERINE 95 



on reduction with sodium in amyl alcohol solution, both 

 cholesterine and cholestenone reacted thus : 



(a) C^O + H 2 = C 17 H 4S 



Cholesterine a-Cholestanol m.p. 126 



{b) C^H 44 + 2H 2 = C, 7 H 48 



Cholestenone /3-Cholestanol m.p. 142 6 



Such a reduction only takes place with a/3 unsaturated 

 ketones, but Windaus (1907) has shown that this is probably 

 not a case of reduction at all, since a-cholestanol can be 

 obtained by the action of sodium amylate, and that it does 

 not contain two atoms of hydrogen more than cholesterine, 

 but, although saturated, is isomeric with that body. He con- 

 cludes that it is formed by a conversion of the open chain of 

 cholesterine to the cyclic form. This, however, is not accepted 

 by Diels and Linn, whose work above-mentioned proves that 

 cholestenone can be reduced. They showed also that the 

 ft cholesterine obtained, when treated with sodium and amyl 

 alcohol, gives a-cholestanol. They consider that sodium amylate 

 possesses reducing properties, since cholestenone when treated 

 with it, 1 gives not /3, but a-cholestanol. 



In 1906 Windaus proved that cholestenone, when reduced 

 by sodium amalgam, gives an unsaturated pinacone C 64 H 86 or ^C^ 

 thus : 



HO OH 



/ \ 



C^H^CO + H 2 + CO . CaHtf = CjgH^. C ■ C . CjgH^ 



According to Harries 2 all unsaturated ketones, except those 

 with the double link in the a/3 position, react in this way, 

 giving a pinacone. Those unsaturated in the a/3 position give 

 a saturated dimolecular diketone : 



CO CO CO CO 



Supposing next that the double link might be in the fiy position, 

 Windaus heated the ketone for a long time with 3 per cent, 

 alcoholic hydrochloric acid, with 10 per cent, alcoholic potash, 

 and finally with diethylamine at 160 . These reagents, which 



1 Bar. 41, 554- ' Ann. der Ch. 330, 213. 



