334  Developments  in  Organic  Compounds.    { Am,juiyr,'i9?i!rm' 
Of  greater  importance  is  the  replacement  of  the  benzoyl  group 
in  cocain  by  other  acid  radicals,  the  anaesthetic  properties  are 
either  lessened  or  disappear  entirely. 
Filehne  thought  that  the  benzoic  acid  rest  was  necessary,  on  the 
ground  that  atropin,  Homatropin  and  the  benzoic  derivatives  of 
other  alkaloids,  as  morphin,  hydrocotarnin  and  quinin,  possessed 
local  anaesthetic  action. 
CH2  CH  CH2 
I  I 
NCH3        CH.OH  Tropin 
I  I 
CH2  CH  CH2 
CH,  CH  CH  .  COOH 
Ecgonin 
NCH3  CH.OH 
CH.,  CH  CH2 
For  the  development  of  the  action  of  cocain  the  position  and  union 
of  the  OH  and  COOH  groups  are  of  great  importance,  hence  the 
stereo  chemical  configuration  of  the  ecgonin  nucleus  is  essential  in 
conjunction  with  the  anchoring  benzoyl  group.  The  methyl  group 
covers  the  acid  and  irritating  characters  of  ecgonin. 
Further,  the  derivatives  of  tropin,  which  do  not  contain  a 
carboxyl,  the  addition  of  a  methyl  group  is  not  essential  for  action. 
On  the  other  hand,  the  presence  of  an  esterized  carboxyl  increases 
activity.  The  mydriatic  effect  stands  likewise  in  close  relationship 
to  the  fundamental  base  (a  pyrrolidin),  but  the  localizing  action 
is  governed  only  by  aromatic  acid  radicals,  as  is  the  case  in  atropin 
and  homatropin.  Based  on  the  view  of  Merling,  that  cocain  was 
made  up  of  two  ring  nuclei,  and  that  one,  a  methylated  piperidin, 
was  the  active  base,  several  products  were  synthesized  from  the 
methylated  base  triaceton  alkamin,  namely 
CH9  CH  CH.COO.CH, 
Cocain 
N.CH3  CH.O.C6H5CO 
Benzoyl-methyl-ecgonin 
CH9-  _CH  CH9 
