44 
Theobromine. 
(Am.  Jour.  Phaim. 
\      Jan.,  1884. 
menstruum.  When  anhydrous  quinine  is  dissolved  in  dry  benzene,  it 
crystallizes  out  in  needles  containing  a  large  quantity  of  benzene, 
which  is  gradually  given  off  until  only  1  mol.  benzene  is  retained. 
Cinchonidine  crystallizes  from  benzene  without  water,  but  with  1  mol. 
benzene,  with  which  it  readily  parts.  The  benzene  employed  in  these 
experiments  was  carefully  purified.  The  authors  recommended  the 
following  test  for  the  purity  of  quinine:  0  7  gram  of  the  quinine  sul- 
phate to  be  tested  is  dissolved  in  20  drops  of  hydrochloric  acid  and 
7  cc.  of  water;  7  cc.  of  benzene  are  added,  and  the  whole  warmed, 
and  then  shaken  up  with  cc.  of  dilute  ammonia.  The  benzene 
layer  is  separated,  the  quinine  hydrate  allowed  to  crystallize  out  and 
filtered  off ;  the  separation  of  feathery  crystals  then  indicates  the  pres- 
ence of  cinchonidine.  These  crystals  contain  a  large  quantity  of 
quinine.  Less  than  1  per  cent,  of  cinchonidine  can  be  recognized  in 
this  way.  The  crystals  must  be  sought  for  within  the  liquid,  not  on 
the  surface,  The  quantities  and  method  of  procedure  given  above 
must  be  strictly  followed  in  order  to  ensure  success.  Absolutely  pure 
benzene  is  not  necessary  for  this  test:  the  benzene  should,  however, 
crystallize  when  placed  in  a  freezing  mixture. — Jour.  Chem.  Soc> 
Nov.,  1883,  from  Chem.  News  [48],  4. 
THEOBROMINE. 
By  E.  Schmidt  and  H.  Pressler. 
To  prepare  theobromine,  the  authors  mix  cacao  which  has  been  freed 
from  oil  by  pressure,  with  half  its  weight  of  calcium  hydroxide,  and 
boil  repeatedly  with  80  per  cent,  alcohol.  After  recrystallizing  the 
residue  obtained  from  the  evaporation  of  the  alcohol,  the  theobromine 
forms  a  white  crystalline  powder.  It  is  anhydrous,  and  sublimes  at 
about  290°  without  melting.  Its  salts  are  obtained  by  dissolving  the 
base  in  concentrated  acids,  and  resemble  those  of  caffeine  in  their  insta- 
bility, being  decomposed  by  contact  with  water  or  alcohol.  The 
hydrobromide,  C7H8N402,HBr  -j-  H20,  forms  colorless  transparent 
platy  crystals,  which  lose  their  water  at  100°  together  with  a  part  of 
the  hydrobromic  acid.  The  hydrochloride,  C7H8N402,HC1  +  H20, 
crystallizes  in  colorless  rosette-like  groups  of  needles  which  lose  both 
water  and  hydrochloric  acid  at  100°.  The  platinoehloride  (C7H8N402)2, 
H2PtCl6  +  4H20,  has  been  described  by  Glasson.    According  to  the 
