268 
Developments  in  Organic  Compounds.  { 
Am.  Jour.  Pharm. 
June,  1901. 
/ 
och3 
C17H 
15- 
Thebai'n. 
NO  .  OCH3 
Pyrocatechol  (C6H4(OH)2i.2.)  through  conversion  into  guaiacol 
develops  an  irritating  action  on  the  spinal  cord. 
Observations  prove  that  it  is  not  the  hydroxyl  groups  in  them- 
selves nor  always  the  terminal  groups  that  determine  solely  the 
action  of  a  substance,  but  the  character  and  complexity  of  the  mole- 
cule. However,  these  groups  assist  in  bringing  the  entire  molecule 
into  action  with  certain  chemical  compounds  in  the  organism. 
When  the  reactive  group  which  exerts  the  selective  action  of  the 
compound  in  the  organism  is  slightly  altered  or  covered,  then  under 
conditions  we  can  prevent  the  action  of  the  entire  compound. 
Between  such  terminal  groups  as  hydroxyl  or  methoxyl  and  certain 
nerve  centers  or  points  in  the  organism  where  chemical  substances 
react,  definite  chemical  relations  must  exist.  Through  changes  in 
these  terminal  groups  we  are  able  to  move  the  point  of  attack  of 
the  substance  or  to  render  it  absolutely  inactive,  but  as  long  as  it 
remains  active,  the  fundamental  characters  of  its  action  (although 
frequently  modified)  always  manifest  themselves,  as  for  example 
the  alkaloids  and  their  derivatives. 
The  replacement  of  a  hydroxyl  by  an  alkyl  rest  renders  the  entire 
body  chemically  and  pharmacologically  more  resistant  to  oxidation 
in  the  system.  Alkyl  groups,  more  especially  the  ethyl,  impart  a 
narcotic  effect.  This  narcotic  and  analgesic  action  is  independent 
of  the  chemical  character  of  the  substance,  it  being  a  specific  prop- 
erty of  this  group  alone.  The  methyl  group  exerts  a  like  effect, 
but  much  weaker  and  less  certain.  Higher  alkyl  rests  present  no 
advantages  over  the  ethyl.  Thus,  through  the  introduction  of  an 
oxyethyl  group  into  caffeine  (ethoxycaffeine)  an  additional  narcotic 
action  is  developed. 
Disulfones  which  contain  ethyl  ( —  C2H5)  groups  are  active,  and 
the  intensity  of  effect  evidently  depends  upon  the  number  of  such 
groupings  contained  in  the  molecule. 
INTRODUCTION  OF  ALKYL  RESTS. 
