134 
Oupreine  and  Homoquinine. 
/Am.  Jour.  Pharm, 
X     March,  1886. 
flocculent  precipitate  when  a  solution  of  the  hydrochlorate  is  mixed 
with  platinum  chloride.  The  precipitate  soon  changes  into  small  flat 
needles,  very  sparingly  soluble  in  hot  water,  more  readily  in  dilute 
acid.  The  water  of  crystallization  is  not  entirely  driven  off  under 
130°  C. 
Cupreine  combines  with  bases  as  well  as  with  acids.  For  complete 
solution  in  caustic  soda  or  caustic  potash  a  slight  excess  of  caustic 
alkali  is  requisite,  and  Dr.  Hesse  considers  that  this  is  owing  to  the 
relative  solubility  of  the  compounds  formed.  When  equal  molecular 
proportions  of  cupreine  and  soda  or  potash  are  mixed  and  the  solution 
shaken  with  ether  a  small  portion  of  the  alkaloid,  from  J  to  tu  is  dis- 
solved by  the  ether,  but  this  may  be  prevented  by  using  some  excess 
of  alkali. 
The  potash  compound  is  very  soluble  in  water;  on  evaporating  the 
solution  or  on  adding  caustic  soda  it  separates  in  a  gelatinous  state. 
The  soda  compound  is  similar  to  the  above;  when  mixed  with 
excess  of  of  caustic  soda  and  warmed  the  jelly  dissolves,  and  on  cooling 
colorless  crystalline  laminae  of  a  silky  lustre  are  formed. 
The  lime  compound. — When  a  solution  of  the  potash  compound  is 
mixed  with  calcium  chloride  a  copious  precipitate  of  the  lime  com- 
pound is  formed.  It  is  moderately  soluble  in  boiling  water,  but  little 
in  cold  water.    The  hot  solution  becomes  gelatinous  on  cooling. 
The  compound  with  lead  oxide  is  formed  when  a  solution  of  the 
soda  compound  is  mixed  with  an  equivalent  quantity  of  lead  acetate 
solution  as  a  yellow  flocculent  precipitate  that  is  very  sensibly  soluble 
in  cold  water  and  has  a  strong  alkaline  reaction. 
The  compound  with  silver  oxide  is  obtainable  in  a  similar  manner 
as  a  yellow  flocculent  precipitate  that  is  moderately  soluble  in  cold 
water.    This  solution  has  a  strong  alkaline  reaction. 
The  foregoing  results  led  Dr.  Hesse  to  the  opinion  that  cupreine 
might  contain  phenolhydroxyl,  and  that  by  the  action  of  acetic  anhy- 
dride a  derivative  might  be  obtained,  in  which  the  phenol  character 
was  extinguished.  To  determine  this  point,  which  turned  out  to  be 
as  he  anticipated,  dry  cupreine  was  mixed  with  acetic  anhydride,  in 
which  it  dissolved  after  heating  to  85°  C.  for  some  time.  When  the 
reaction  had  been  continued  a  few  hours  water  was  added,  and  the 
liquid  almost  neutralized  by  careful  addition  of  ammonia.  By  pre- 
cipitating the  base  with  ammonia  and  dissolving  it  in  ether  colorless 
hexagonal  plates  were  obtained  on  evaporation,  consisting  of  diacetyl- 
