Am.  Jour.  Pharm.  1 
March,  1886.  J 
Cupreine  and  Homoquinine. 
137 
readily  soluble  in  caustic  soda  and  when  heated  with  an  excess  did  not 
appear  to  be  much  altered. 
In  these  compounds  of  methyl  cupreine  the  phenolhydroxyl  main- 
tains its  full  influence ;  but  there  was  reason  to  expect  that  by  suitable 
treatment  they  might  be  converted  into  methylcupreine  methyl  or 
quinine  methyl  compounds  after  the  manner  represented  by  the  follow- 
ing equation:  , 
C19H21MN202.CH2I  -f  CH3I=MI + C19H2l(CH3)N202,CH3L 
But  experiment  did  not  confirm  this  anticipation  and  on  the  contrary 
dimethylcupreine  compounds  were  obtained.  In  operating  with  the 
silver  compound  dimethylcupreine  hydroxide  was  easily  obtained,  a 
highly  basic  substance  giving  a  reddish-yellow  solution  in  water. 
When  slightly  supersaturated  with  hydrochloric  acid  and  mixed  with 
potassium  iodide  solution  dimethylcupreine  iodide  crystallized  out  in 
brilliant  reddish-yellow  laminae,  sparingly  soluble  in  water,  readily  in 
acid,  alkalies  and  alcohol,  having  the  composition  represented  by  the 
formula  C19H22N202(CH3I)2+5  H20. 
The  attempts  to  effect  a  synthesis  of  quinine  or  its  methyliodide 
compound  having  so  far  failed  the  sodium  compound  of  the  iodide  was 
again  subjected  to  the  action  of  methyl  iodide  in  closed  tubes  at  100°  C. 
The  solution  thus  formed  was  dark  brown;  it  had  no  basic  reaction, 
and  when  mixed  with  water  deposited  a  brown  resinous  substance. 
As  sodium  iodide  was  formed  this  resin  might  perhaps  have  been 
dimethylquinine  iodide,  but  it  did  not  appear  to  be  that  compound. 
It  dissolved  readily  in  caustic  soda  and  in  dilute  acids,  and  undoubtedly 
contained  phenolhydroxyl  still  unaltered.  In  any  case  Dr.  Hesse  is  of 
opinion  that  the  hydrogen  of  the  phenolhydroxyl  present  in  cupreine 
offers  great  resistance  to  the  substitution  by  methyl. 
Dr.  Hesse  then  proceeds  to  discuss  the  nature  of  homoquinine,  and 
in  reference  to  the  opinion  expressed  by  Paul  and  Cownley  that  the 
differences  presented  by  it  from  cupreine  and  quinine  and  by  the  cor- 
responding salts  may  be  taken  as  indications  that  homoquinine  is  a 
distinct  alkaloid,  he  puts  forward  the  view  that  these  differences  may 
be  due  to  the  combination  of  quinine  with  cupreine.  Hence  he  thinks 
that  the  ready  solubility  of  homoquinine  in  alcohol  and  the  impossi- 
bility of  obtaining  it  from  this  solution  in  any  other  than  the  amor- 
phous condition  is  not  surprising,  and  further,  that  the  appearance  and 
behavior  of  some  homoquinine  salts  also  furnish  as  little  evidence  of 
the  individuality  of  homoquinine. 
