Am.  Jour.  Pharm. ) 
Sept.,  1883.  i 
Constitution  of  Atropine. 
465 
method  for  the  preparation  of  this  base  is  to  heat  a  mixture  of  tropine 
(2  parts),  glacial  acetic  (12  parts),  and  concentrated  sulphuric  acid  (46 
parts).  In  addition  to  the  properties,  etc.,  already  given,  the  vapor 
density  has  been  determined,  and  found  to  be  118.  Tropidine  is  solu- 
ble in  acids,  in  ether,  and  alcohol,  scarcely  soluble  in  soda ;  its  aqueous 
solution  has  a  strongly  alkaline  reaction.  Tropidine  hydrochloride 
forms  hygroscopic  crystals,  soluble  in  water.  The  hydrohromide  is 
similar,  but  not  quite  so  hygroscopic.  The  picrate  crystallizes  in  yel- 
low needles,  very  sparingly  soluble  in  cold,  somewhat  more  so  in  hot 
water.  The  periodide  forms  brown  prisms  (m.  p.  92-93°),  soluble  in 
alcohol.  With  methyl  er  ethyl  iodide,  tropidine  yields  a  mono-methyl 
or  ethyl-derivative,  which  is  crystalline  and  forms  well-defined  crys- 
talline platino-  and  auro-chlorides.  The  action  of  hydriodic  acid  and 
phosphorus  on  tropine  results  in  the  formation  of  hydrotropine  iodide 
(m.  p.  115°);  if,  however,  during  the  reaction,  the  tube  be  heated  to 
150°  or  above,  tropidine  and  its  periodide  are  the  products,  owing  to  a 
secondary  dehydrating  reaction  resulting  in  the  conversion  of  tropine 
into  tropidine.  The  formation  of  metatropine  from  hydrotropine 
iodide  is  then  discussed,  and  the  conclusion  arrived  at  is  that  tropine 
is  a  nitrogenous  alcohol  of  which  the  tropeines  are  the  ethereal  deriva- 
tives. This  view  is  supported  by  the  author's  work  on  alkines,  which 
are  a  class  of  bodies  quite  analogous  to  the  tropeines.  Then  follow 
detailed  accounts  of  the  following  experiments :  Decomposition  of 
dimethyltropine  by  heat ;  the  production  of  tropilene  from  methyltro- 
pidine  iodide  and  tropiledene  from  dimethyltropine  iodide;  the  decom- 
position of  methyltropine,  methyltropine  chloride  and  iodide  by 
potash,  the  principal  products  being  large  quantities  of  di-  and  small  of 
tri-methylamine  ;  the  oxidation  of  tropilene  into  adipic  acid,  and  finally 
the  decomposition  of  tropidine  by  bromine,  by  which  ethylene  dibro- 
mide  and  dibromomethylpyridine  are  obtained.  The  inferences  there 
deduced  are  enlarged  upon,  and  the  formula  C5H7(C2H40.CO.CHPh. 
CH2.0H)NMe,  proposed  for  atropine. — Jour.  Chem.  Soc,  June,  1883, 
from  Annalen,  217,  74-149. 
30 
