Am  jour.  Pharm.  j     Resins  and  Relations  to  Terpenes.  59 
February,  1913.    j  1  ° 
amorphous  resin  which  he  carefully  studied  and  gave  the  formula 
C20H30O3,  apparently  an  oxyabietic  acid. 
Heldt,5  in  an  exhaustive  study  of  the  resins,  produced  common 
sylvic  acid  by  oxidizing  a  polymerized  form  of  turpentine  according 
to  the  following  equation : 
2(GoHis)   or  C20H32  +  O2  =  C20H32O2,  sylvic  acid, 
and 
C20H32O2  +  O  =  GoH3„02  +  H2O,  or  abietic  acid. 
This  work  has  been  repeated,  but  without  obtaining  either  sylvic 
or  abietic  acids. 
One  of  the  most  interesting  communications  along  this  line  was 
presented  by  Bruylaut.  He  obtained,  by  a  method  not  given,  a 
polymer  of  pinene  which  he  represented  as  a  condensation  of  two 
molecules  of  pinene  or  dipinene.  By  oxidizing  this  substance  he 
obtained  an  acid  which  had  the  empirical  formula  for  abietic  acid : 
C3H7 
CeH6< 
I  CH3 
[  CH3 
CeHe  < 
C3H502 
No  details  of  the  work,  however,  were  given. 
Work  on  the  condensation  of  the  terpenes  has  been  in  progress 
at  the  University  of  Minnesota  for  several  years.  Before  de- 
scribing some  of  these  experiments,  however,  it  may  be  of  interest 
to  briefly  trace  the  work  on  the  synthesis  of  the  terpenes  them- 
selves. It  was  observed  early  in  this  work  that  when  pinacone  is 
treated  with  bromine,  an  extremely  complex  reaction  takes  place 
and  among  the  products  formed  are  isopropyl  alcohol  and  sub- 
stances belonging  to  the  terpenes.  It  was  found,  however,  on 
carefully  studying  the  reaction,  that  Baeyer  had  already  observed 
this  fact,  but  had  not  followed  out  the  reaction,  doubtless  on 
account  of  the  extreme  complexity  of  the  reaction.  If,  however, 
we  take  into  consideration  these  two  substances,  the  reaction  ma^ 
be  represented  as  follows : 
6C6H1402  —  2QHsO  +  3doH16  +  10H2O. 
6  Ann.,  63-48. 
