AmjJu°nue,'i908arm"}     Chemical  Examination  of  Ipomcea  Purpurea.  285 
the  ether  extract,  but  no  crystalline  acid  could  be  isolated.  When 
heated  with  5  per  cent,  alcoholic  sulphuric  acid,  it  likewise  afforded 
products  which  were  very  similar  to  those  obtained  from  the  ether 
extract  of  the  resin. 
IV.  Ethyl  Acetate  Extract. — This  represented  23-8  per  cent,  of  the 
total  resin.  From  this  extract  there  was  isolated  a  very  small 
amount  of  a  new  crystalline  alcohol,  ipuranol,  having  the  formula 
C23H3802(OH)2,  and  melting  at  285-2900  C.  Its  acetyl  derivative 
formed  pearly  leaflets,  melting  sharply  at  1600  C.  The  extract, 
when  fused  with  potassium  hydroxide,  as  also  when  heated  with  5 
per  cent,  alcoholic  sulphuric  acid,  yielded  products  analogous  in 
character  to  those  obtained  from  the  above-described  ether  and 
chloroform  extracts  of  the  resin  by  the  same  treatment. 
V.  Alcohol  Extract. — This  represented  about  one-half  of  the  total 
crude  resin.  When  purified  by  means  of  animal  charcoal,  it  was 
obtained  in  the  form  of  a  perfectly  white  powder,  which,  after  dry- 
ing at  no0  C,  melted  somewhat  indefinitely  between  150  and  160° 
C.    Its  specific  rotatory  power  was  [_a~\D  —  51-64°. 
When  heated  with  5  per  cent,  alcoholic  sulphuric  acid,  this  extract 
like  the  preceding  ones,  yielded  a  small  amount  of  a  neutral  oil, 
formic,  butyric  and  higher  volatile  acids,  and  a  non-volatile  acid 
which  was  readily  soluble  in  water,  together  with  glucose.  In 
addition  to  these  products,  however,  it  afforded  a  quantity  of  a 
new  dihydroxymonocarboxylic  acid,  C13H25(OH)2-C02H,  designated 
ipurolic  acid,  which  crystallizes  in  fine,  colorless,  silky  needles,  melt- 
ing at  100-101°  C.  Several  derivatives  of  this  acid  have  been  pre- 
pared, such  as  its  sodium  salt,  C13H25(OH)2-C02Na,H20 ;  silver  salt, 
C13HL5(OH)2C02Ag  (m.  p.  160°  C);  methyl  ester,  C^H^OH),- 
CO0CH3  (m.  p.  68-69°  C.) ;  the  monomethyl  derivative  of  the  methyl 
ester,  C13H25(OH)(OCH3)C02CH3  (m.  p.  64-65°  C.) ;  and  the  diphenyl- 
urethane  of  the  methyl  ester,  C13H25(0  CO-NH-C6H5)2-C02CH3,  melt- 
ing at  96-97°  C. 
The  above-described  alcohol  extract  of  the  resin,  when  treated  in 
alcohol  solution  with  barium  hydroxide,  yielded,  besides  formic  and 
butyric  acids,  a  quantity  of  optically  active  valeric  acid  (^-methyl- 
ethylacetic  acid),  b.  p.  174-176°  C. ;  [a]D  +  17*95°,  together  with, 
a  mixture  of  acids  which  was  readily  soluble  in  water.  This  mix- 
ture of  acids  was  extracted  successively  with  ether,  chloroform  and 
ethyl  acetate,  when  small  amounts  were  removed  by  each  of  these 
solvents,  the  larger  proportion  being  soluble  only  in  alcohol.  These 
