640  Condurangin.  {Ami&ufi5larm- 
multiply  the  remainder  from  the  subtraction  by  10lQ0  of  the 
equivalent  of  the  alkaloid  in  question.    The  factors  are  evidently  : 
For  anhydrous  quinone,   0*0324 
"  cinchonine,  :   0-0294 
"  codeine  (H20),   0*0317 
"  morphine  (H20),  .  .  .  .  -         ....  0*0303 
—  Comptes  Rendus,  vol.  cxv,  p.  512;  Chcm.  News,  Novbr.  4, 
1892,  p.  223.  
CO  X  DURA  X  GI N.1 
By  G.  Carrara. 
Condurangin  is  a  glucoside,  first  obtained  by  Vulpius,  from  the 
bark  of  Gonolobus  Condurango,  and  considered  by  some  writers  as 
identical  with  vincetoxin  from  Asclepias  Vincetcxicum.  It  may  be 
separated  into  two  parts,  one  of  which  is  soluble  in  water,  the  other 
insoluble.  The  best  method  of  preparing  it,  is  to  extract  the  bark 
with  95  per  cent,  alcohol  in  a  reflux  apparatus,  filter,  distil  off  the 
greater  part  of  the  alcohol,  take  up  with  cold  water,  filter  again,  add 
concentrated  solution  of  ammonium  carbonate,  and  heat  gently.  The 
precipitate  thus  formed  is  washed  with  hot  water,  redissolved  in  cold 
water,  containing,  if  necessary,  a  few  drops  of  alcohol,  basic  lead 
acetate  added,  the  precipitate  thoroughly  washed,  suspended  in 
water,  and  decomposed  with  hydrogen  sulphide;  the  brown  solution 
obtained  is  then  precipitated  with  a  concentrated  solution  of  common 
salt.  The  precipitate,  after  purification,  consists  of  a  mixture  of  the 
two  modifications  of  condurangin.  Insoluble  condurangin  is  precipi- 
tated from  a  benzene  solution  on  the  addition  of  excess  of  light 
petroleum,  as  a  light,  almost  white  powder,  which  melts  at  60-61  °, 
and  has  the  percentage  composition  C3,H3.,Or..  Its  molecular  weight, 
as  determined  by  the  endoscopic  method,  agrees  with  this  formula. 
Soluble  condurangin,  obtained  by  the  evaporation  of  an  aqueous 
extract  of  the  mixed  varieties,  is  a  yellowish  substance  melting  at 
1340.  It  appears  to  have  the  composition  C--H-iO..  but  its 
molecular  weight  could  not  be  determined.  On  boiling  either  of 
these  compounds  with  acids,  the  principal  product  is  a  brown,  pitchy 
substance,  insoluble  in  water.  With  Frohde's  reagent,  an  aqueous 
solution  of  the  soluble  condurangin  yields  a  greenish  coloration,  and 
after  a  time  a  flocculent,  green  precipitate,  the  insoluble  variety, 
suspended  in  water,  gives  no  reaction,  or  only  a  yellowish  coloration. 
