A.ni.  Jour.  Pilar  in. ) 
June,  1891.  j 
Cholesterol. 
299 
of  the  analysis  is  that  Reinitzer's  formula  is  correct.  The  following 
compounds  were  prepared  : 
Potassium  cholesteroxide,  C27H45OK,  was  prepared  by  placing 
potassium  in  an  ethereal  solution  of  cholesterol.  It  agrees  in  all  its 
properties  with  Reinitzer's  sodium  cholesteroxide. 
Cholesteryl propionate,  C27H45.C3H502,  was  prepared  by  heating  a 
mixture  of  cholesterol  with  propionic  anhydride  on  the  water-bath 
for  half-an-hour ;  on  cooling,  it  sets  to  a  fatty  mass  ;  this  is  extracted 
with  ether,  and  the '  propionate  precipitated  from  the  extract  by 
alcohol  in  the  form  of  rhombic  plates;  melting  point  980.  It  is 
easily  soluble  in  ether,  benzene,  and  carbon  bisulphide,  sparingly 
soluble  in  alcohol.  After  fusion,  there  is,  on  cooling,  a  play  of 
colors  observed,  blue,  green,  orange,  and  red,  in  the  order  named, 
by  reflected  light;  the  complementary  colors  are  seen  by  trans- 
mitted light.  In  order  to  use  this  reaction  as  a  test  for  cholesterol, 
the  latter  must  first  be  obtained  in  a  pure  condition  ;  it  may  be 
most  readily  freed  from  the  fats  with  which  it  is  usually  mixed  by 
the  method  of  saponification. 
Cholesteryl  benzoate,  C27H45C7H502.  This  is  best  prepared 
by  the  action  of  benzoic  chloride  on  cholesterol;  and  this  prepara- 
tion may  be  used  for  the  quantitative  estimation  of  cholesterol. 
The  crystals  are  plates  which  show  two  melting  points,  namely, 
145 0  and  1780.  A  compound  with  similar  properties  was  prepared 
from  isocholesterol. 
Cholesteryl  phthalate,  C6H4(COO-C27H45)2,  was  prepared  by  heat- 
ing phthalic  anhydride  and  cholesterol  at  1800,  and  crystals  obtained 
by  the  addition  of  alcohol  to  a  hot  ethereal  solution.  It  is 
sparingly  soluble  in  cold  ether;  melting  point  18-250. 
Cholesteryl  benzyl  ether,  C27H45*OC7H7,  prepared  by  heating 
sodium  cholesteroxide  and  benzyl  chloride  at  ioo°,  was  crystallized 
from  an  acoholic-ethereal  solution  in  thin  plates  melting  at  780. 
Cholesteryl  propionate  dibromide,  C27H45Br2-C3H502.  This  addi- 
tive product  is  similar  to  that  prepared  previously  by  Wislicenus 
and  Moldenbauer.  C27H46Br20  (Afinalen,  146,.  178),  by  the  action 
of  bromine  dissolved  in  carbon  bisulphide  on  pure  cholesterol,  and 
to  that  prepared  by  Reinitzer  (  Wiener  Monatsh.,  1888,  Heft  5),  by 
the  action  of  bromine  on  cholesteryl  acetate.  This  substance  is 
important,  as  the  relation  between  carbon  and  bromine  gives  a  key  to 
the  formula  of  cholesterol.  Cholesteryl  bromobenzoate,  C7H4Br02., 
C27H45,  was  also  prepared  and  analyzed. 
