302 
The  Cinchona  Alkaloids. 
1  Am.  Jour.  Pharm. 
\      June,  1878. 
solution  evaporated  and  the  residue  crystallized  from  hot  dilute  alcohol ; 
the  mother-liquor  retains  the  balance  of  the  amorphous  bases.  The 
author  now  regards  his  first  formula,  C20H26N2O2,  as  incorrect. 
Conquinamina,  C19H24N202,  is  present  with  the  preceding  in  C.  suc- 
cirubra  and  C.  rosulenta,  and  perhaps  in  all  barks  mentioned  above. 
It  crystallizes  in  long  shining  prisms,  which  melt  at  i23°C,  while 
quinamina  melts  at  172°C.  It  is  more  powerfully  dextrogyre  than 
quinamina,  and,  like  it,  is  precipitated  by  chloride  of  platinum  onlv 
from  concentrated  solutions,  and  yields  with  chloride  of  gold  a  yellow 
precipitate,  changing  to  purple,  and  with  hydriodic  acid  a  salt  crystal- 
lizing in  handsome  prisms. 
®)uinamidia,  C]9H24N202,  an  amorphous  alkaloid,  is  formed  when 
quinamina  is  boiled  for  some  time  with  diluted  H2S04  ;  it  is  precipi- 
tated from  an  acid  solution  with  difficulty  by  ammonia,  more  easily  by 
soda,  and  is  easily  soluble  in  .ether.  With  HC1  it  forms  prismatic 
crystals,  sparingly  soluble  in  water,  and  with  chloride  of  gold  a  yellow 
amorphous  precipitate,  soon  turning  purple. 
Apoquinamina,  C19H22N20,  is  isomeric  with  homocinchonidia,  and 
is  formed  by  the  action  of  concentrated  HC1  on  quinamina  and  con- 
quinamina  C19H24N202 — H20=C19H22N20.  It  is  a  white  amorphous 
powder,  very  soluble  in  ether,  alcohol  and  in  diluted  HC1.  The  chlor- 
hydrate  is  amorphous  ;  chloride  of  platinum  causes  a  yellow  amorphous 
precipitate  (C19H22N2OHCl)2-j-PtCl4 ;  chloride  of  gold  gives  a  similar 
precipitate,  which  does  not  turn  purple. 
®hiinamicina,  C19H24N202,  is  formed  when  quinamina  and  probably 
also  conquinamina,  in  the  form  of  sulphate,  is  heated  to  ioo°C.  The 
residue  is  dissolved  in  cold  water,  precipitated  by  sodium  bicarbonate, 
and  the  alkaloid  freed  from  quinamidina  by  repeated  solution  in  acetic 
acid  and  precipitation  with  bicarbonate.  Quinamicina  is  a  white  amor- 
phous powder,  which  fuses  between  95  and  I02°C,  is  slightly  dextro- 
gyre and  freely  soluble  in  ether  and  in  diluted  H2S04 ;  the  latter  solu- 
tion yields  yellow  precipitates  with  the  chlorides  of  platinum  and  of 
gold. 
Protoquinamiana,  C17H20N2O,  is  formed,  like  the  preceding,  by 
raising  the  temperature  to  above  iOO°C,  preferably  to  between  120 
and  I30°C.  The  sulphate  is  nearly  insolube  in  cold  water.  The 
alkaloid  is  insoluble  in  ether,  but  dissolves  readily  in  acetic  acid,  form- 
ing a  brown  solution,  from  which  it  is  precipitated  by  ammonia  or 
