424 
Isocinnamic  Acid  in  Cocaine  Alkaloids.  { 
Am.  Jour.  Pharm. 
Aug.,  1890. 
gradually  rises  to  3000.  The  distillate  consists  principally  of  cin- 
namic  acid  (90  per  cent.),  but  on  prolonged  boiling  cinnamene  is 
also  produced.  Isocinnamic  acid  is  almost  quantitatively  converted 
into  cinnamic  acid  when  it  is  boiled  for  about  a  minute  under  the 
ordinary  pressure. 
Hydrocinnamic  acid  (m.  p.  480)  is  obtained  when  isocinnamic  acid 
is  dissolved  in  soda,  and  the  solution  treated  in  the  cold  with  sodium 
amalgam  of  3  per  cent.;  the  yield  is  almost  quantitative.  When  iso- 
cinnamic acid  is  treated  with  bromine  in  cold  carbon  bisulphide 
solution,  it  is  converted  into  phenyl-a/3-dibromopropionic  acid  (m.  p. 
1960);  the  yield  is  on  the  average  45-50  per  cent,  of  the  acid 
employed.  Methyl  isocinnamate,  under  the  same  conditions,  is 
converted  into  methyl  phenyl-a/3-dibromopropionate  (m.  p.  1 1 7°). 
Isocinnamic  acid  is  not  changed  when  treated  with  iodine  in  cold 
carbon  bisulphide  solution,  but  on  warming  it  is  converted  into 
cinnamic  acid. 
Isocinnamic  acid  dissolves  almost  completely  in  hydrobromic 
acid,  and  in  about  24  hours  it  is  completely  converted  into  phenyl- 
/3-bromopropionic  acid  (m.  p.  1 37°)  ;  it  is  completely  converted  into 
phenyl-^-chloropropionic  acid  (m.  p.  1260)  when  it  is  dissolved  in  a 
saturated  solution  of  hydrogen  chloride  in  glacial  acetic  acid  and 
the  solution  kept  for  three  to  four  days,  whereas  cinnamic  acid 
under  the  same  conditions  is  only  very  partially  converted  into  the 
same  additive  compound. 
Isocinnamic  acid  and  cinnamic  acid  both  require  the  same  quan- 
tity (4  mols.)  of  potassium  permanganate  for  complete  oxidation  to 
benzoic  acid. 
Isocinnamic  acid  occurs  in  storax ;  from  about  2  kilos,  of  crude 
cinnamic  acid  from  this  source,  the  author  isolated  about  2  grams 
of  pure  isocinnamic  acid  by  the  method  described  above. 
The  relationship  existing  between  cinnamic  acid  and  isocin- 
namic acid  can  be  explained  by  accepting  Wislicenus'  hypothesis;  in 
accordance  with  this  view,  the  acids  would  have  the  constitution  • 
PhCH 
COOHOH 
and 
Ph-CH 
H-CCOOH 
respectively. 
The  behavior  of  isocinnamic  acid  is  in  complete  accordance  with 
the  view  that  it  is  a  labile  form  of  cinnamic  acid. 
