^"^june^sS^^"^*}        Terpenes  and  their  Derivatives.  309 
unstable  additive  compounds,  but  according  to  its  molecular  refraction 
is  a  saturated  compound.  It  is  optically  inactive,  and  optically  inac- 
tive dipentene  dihydrochloride  is  formed  when  hydrogen  chloride  is 
passed  into  warm  cineole.   Of  the  nine  possible  formulse  for  cineole  as 
^CHg'  CH2\ 
a  paracymene-derivative,  only  one,  CPr^  O  ^CMe,  is  in  keep- 
ing  with  these  facts. 
Terpin,  C10H20O2,  is  an  optically  inactive  compound,  formed  by  the 
action  of  alcoholic  nitric  acid  on  pinene.  It  is  a  saturated  compound, 
containing  two  hydroxy  1-groups.  By  the  action  of  hydrogen  chloride 
on  terpin,  a  compound,  CioHigCla,  is  formed,  identical  with  the  addi- 
tive-product from  dipentene  and  hydrogen  chloride.  Boiled  with  dilute 
mineral  acids,  terpin  is  first  converted  into  terpineol,  CioHigO,  and  then 
into  dipentene.  Terpineol  contains  one  hydroxyl-group,  has  one  dou- 
ble bond,  and  is  optically  active.  In  all  probability  terpin  is  a  dihy- 
droxy-,  terpineol  a  monohydroxy-derivative  of  dipentene. 
Camphor,  CioH^gO,  is  probably  also  a  derivative  of  the  terpenes  and 
paracymene,  as  it  is  easily  obtained  from  camphene.  From  the  molecu- 
lar refraction  of  ethylcamphor,  it  is  concluded  that  camphor  contains 
no  double  bond.  Borneol,  the  secondary  alcohol  derived  from  cam- 
phor, is  also  a  saturated  compound.  From  bornyl  chloride  CioHj^ 
CI,  by  elimination  of  HCl,  camphene  is  obtained,  so  that  borneol  like 
camphor  appears  to  be  related  to  that  terpene. 
Isomeric  with  camphor  are  myristicol  and  absinthol.  The  first  of 
these  is  an  alcohol,  and  contains  two  double  bonds.  By  the  action  of 
phosphorus  chloride  a  compound  CjoHigCl  is  obtained,  which  on  elim- 
ination of  HCl  yields  paracymene.  Myristicol  is,  therefore,  probably 
a  phenol  of  hydrated  paracymene.  Of  absinthole  but  little  is  known ; 
it  is  neither  an  aldehyde  nor  a  ketone,  but  the  oxygen  is  probably  com- 
bined as  in  cineol. 
Carvol  and  carvacrol,  CjqHi^O.  The  molecular  refraction  is  found  to 
support  Ooldschmidt's  views  of  the  relation  these  substances  bear  to 
one  another. 
Safrol,  CiqHiqO,  contains  according  to  the  molecular  refraction  four 
double  bonds,  and  from  what  is  known  of  its  chemical  behavior  has 
most  probably  the  constitution  CsHg-CgHg  '<q>  CHg.    The  recently 
discovered  shikimol  appears  to  be  identical  with  safrol.  Both  are 
optically  inactive. 
