Am.  Jour.  Pharm. 
Oct.,  1884. 
Quinine  and  Homoquinine. 
523 
mans,  jun.,1  otherwise,  up  to  about  4  per  cent,  of  cinchonidine  sul- 
phate might  be  "  found  "  in  a  quinine  sulphate,  obtained  from  cuprea 
bark  in  which  not  a  trace  was  present.  This  mistake  may,  however, 
be  easily  avoided,  by  previously  determining  the  amount  of  water  in 
the  tartrate,  and  as  I  have  done  in  my  optical  quinine  test,2  starting 
from  the  anhydrous  salt. 
III.  Conversion  of  Homoquinine  into  Quinine. 
Some  observations  which  I  made  during  the  investigation  of  cuprea 
bark  agreed  pretty  well  with  the  presumption  that  under  certain  con- 
ditions homoquinine  might  change  into  quinine.  To  ascertain  these 
conditions  I  first  heated  the  alkaloid  to  100°  C.  with  dilute  hydro- 
chloric or  sulphuric  acid,  sometimes  in  open  vessels  and  sometimes  in 
closed  tubes,  but  without  result.  Hydrochloric  acid  of  specific  gravity 
1*125  acted  no  better;  but  upon  heating  the  latter  solution  some  hours 
to  140°C,  methyl  chloride  and  apoquinine  wTere  formed,  as  with  qui- 
nine. Nevertheless,  I  was  unable  to  separate  quinine  from  this  solu- 
tion by  means  of  ammonia  before  this  formation  took  place.  If, 
however,  soda  lye  were  used  for  the  precipitation  of  the  alkaloid,  a 
certain  quantity  of  quinine  now  resulted.  In  consequence  of  this 
observation  I  was  now  able,  by  repeated  precipitations  with  soda  •  lye, 
shaking  the  precipitates  with  ether,  and  this  solution  with  very  dilute 
sulphuric  acid,  to  convert  homoquinine  completely  into  quinine.  The 
conversion  is  essentially  accelerated  by  heating  the  base  with  soda  lye, 
a  previous  heating  of  the  acid  solution  being  thereby  made  unnecessary. 
From  the  quinine  obtained  through  conversion  of  homoquinine  the 
neutral  sulphate  was  prepared,  which  gave 
I.  0-5425  gram  at  120°  0*0893  H20. 
II.  0-7320  gram  at  103°  0-1170  H20. 
III.  0-4625  gram  at  120°  0*0720  H20. 
Calculated  for  Found 
(C20H24N2O2)2,SO4H2+8  H20  I.         II.  III. 
H20    .    .    16-17  16-46      15-97  15'54 
This  salt  effervesced  rapidly  in  dry  air  and  then  contained  still  2 
molecules  of  H20.  On  the  other  hand,  the  dried  sulphate  quickly 
took  up  4  to  4*6  per  cent,  of  water. 
1  Annalen,  clxxxii,  65. 
2  Annalen,  ccv,  217. 
