Amiu°]y?if95arm'}  The  Violet  Perfume.  353 
(b)  lonegenondicarboxylic  Acid, 
CH3^  /CH3 
'  C  —  COOH 
XX>OH 
On  crystallization  from  dilute  alcohol  forms  clear  vitreous  prisms 
with  difficulty  soluble  in  hot  water ;  soluble  in  ether,  alcohol,  acetic 
ether,  chloroform  and  boiling  benzol.  When  rapidly  heated  it 
melts  at  130°-!  310,  but  when  gradually  heated  it  melts  a  few 
degrees  lower,  and  is  converted  into  the  anhydride  which  crystal- 
lizes from  light  petroleum  ether  in  long,  white  needles,  M.  P.  105  °. 
The  acid  is  bibasic  and  its  calcium  salt  when  distilled  with  soda 
lime  yields  Cymene. 
(c)  Ionegenalide 
CH3-C6H3-C-  CHOH 
Leo  0-1 
On  crystallization  from  benzol  it  forms  transparent  plates,  M.  P. 
1750.  It  possesses  feeble  acid  properties  and  has  the  composition 
of  the  semi-aldehyde  of  ionegenondicarboxylic  acid.  It  does  not, 
however,  appear  to  contain  the  aldehyde  group  and  is,  therefore, 
probably  the  aldehyde  of  the  anhydride  shown.  It  is  readily  con- 
verted by  oxidation  into  ionegenondicarboxylic  acid.  Ionene  on 
direct  oxidation  with  K2Mn208  yields  Ionegenontricar  boxy  lie  acid, 
CH3^  ^CH3 
(4)         C  —  CO  .  COOH 
HOOCC6H3/(2) 
NJOOH 
On  crystallization  from  hot  water,  it  forms  white  granular  crys- 
tals, sparingly  soluble  in  water,  alcohol,  ether  and  acetic  ether  ;  in- 
soluble in  benzol,  chloroform  and  ligroin.  It  crystallizes  with  2 
molecules  of  H.20.  When  rapidly  heated  it  melts  at  I40°-I45°and 
decomposes  above  this  temperature  forming  the  anhydride.  The 
final  product  in  the  oxidation  of  Ionene  acid  and  of  all  intermediate 
oxidation  products  described  is  Ionegenontricarboxylic  acid  and  is 
identical  with  that  obtained  from  Irene. 
