276    Chemical  Examination  of  Ipomcea  Purpurea.     { Am  june?i5»arm 
product  separated,  which  was  removed  and  found  to  be  the 
unchanged  ester.  The  ad  iition  of  light  petroleum  to  the  filtrate 
caused  the  separation  of  a  substance  which  melted  at  95-960  C. 
This  was  dissolved  in  ether,  and  such  an  amount  of  light  petroleum 
added  that  the  solid  separated  slowly.  By  this  means  it  was 
obtained  in  the  form  of  small  rosettes,  which  melted  at  96-970  C, 
and  after  two  recrystallizations  the  melting  point  remained 
unchanged.  The  compound  was  then  analyzed  with  the  following 
results  : 
(I.)   o- 1 100  gave  0-2572  C02  and  00798  H20.  C  =  68-2  ;  H  —  8-1. 
(II.)  00352  gave 0-0882  C02  and  00250  H20.  C  =  68-3  ;  H  =  7-9- 
0-1562  gave  7*0  c.c.  of  moist  nitrogen  at  759  mm.  and  190  C. 
N  =  5-6. 
Co9H40O6N2  requires  C  =  68-o ;  H  =  7  8  ;  N  =  5-5  per  cent. 
These  results  prove  conclusively  that  the  above  substance  was  a 
di-p  he  ny lure  thane  of  methyl  ipurolate.  Ipurolic  acid,  therefore,  is  a 
dihydroxymonocarboxylic  acid. 
Methyl  Monomethylipurolate ,  C13H25  (OH)  (OCH3)  C02CH3. — A 
quantity  (2  5  grammes)  of  methyl  ipurolate  was  heated  in  a  sealed 
tube  with  an  excess  of  methyl  iodide  and  dry  silver  oxide  at  100- 
1100  C.  for  four  hours.  The  product  was  then  filtered,  the  filter 
with  its  contents  being  thoroughly  washed  with  ether.  After  the 
removal  of  the  ether,  a  residue  was  obtained,  which,  when  recrys- 
tallized  from  light  petroleum,  separated  in  small  needles  melting  at 
64-65 0  C,  and  this  melting  point  was  not  changed  by  further 
crystallization.    The  substance  was  then  analyzed. 
0  0848  gave  0  2066  C02  and  0  0834  H20.  C  =  66  4    H  =  10  9. 
C16H3204  requires  C  —  66-7  ;  H  ==  H  i  per  cent. 
It  is  evident  that  by  the  above  treatment  only  one  of  the  hydroxyl 
groups  in  methyl  ipurolate  had  become  methylated. 
Hydrolysis  of  the  Alcohol  Extract  of  the  Resin,  with  Barium 
Hydroxide. 
A  quantity  (200  grammes)  of  the  purified  resin  was  dissolved  in 
alcohol  (rooo  c.c),  and  a  freshly  prepared,  cold,  saturated  solution 
of  barium  hydroxide  gradually  added  until  the  liquid  showed  an 
alkaline  reaction.  The  liquid  was  then  kept  at  a  temperature  of 
about  350  C,  small  portions  of  solution  of  barium  hydroxide  being 
