Am.  Jour.  Pharm. 
July,  1886. 
Derivatives  of  Papaverine. 
355 
in  glacial  acetic  acid  and  in  moderately  dilute  mineral  acids ;  the  best 
solvent  is  chloroform.  When  treated  with  concentrated  sulphuric 
acid,  it  acquires  a  yellowish-red  color,  which  becomes  dark  violet 
when  the  solution  is  warmed.  The  hydrochloride,  with  2J  mols. 
H20,  forms  long,  lustrous,  slender,  yellow  crystals;  the  acid  sulphate 
crystallizes  in  long,  slender,  lemon-yellow  needles.  Both  salts  are 
decomposed  by  water.  The  plantinochloride,  with  1  mol.  H20,  forms 
small,  lustrous,  orange-colored  prisms.  The  phenylhydrazine-compound 
crystallizes  from  dilute  alcohol  in  small  reddish  aggregates;  it  melts 
at  80-81°. 
Dimethoxycinchoninic  acid,  C12HnN04  Hh  2H20,  is  formed  in  small 
quantities  in  the  preparation  of  papaveraldine,  and  is  best  obtained  by 
oxidizing  10  gins,  of  papaverine  with  a  5  per  cent,  solution  of  50 
gms.  of  potassium  permanganate.  It  forms  yellowish  needles,  which 
melt  at  200-205°  with  effervescence,  and  is  readily  soluble  in  alcohol 
and  hot  water.  The  ammonium  salt  is  readily  soluble.  The  hydro- 
chloride forms  yellow,  slender,  lustrous  needles ;  the  plantinochloride 
crystallizes  in  groups  of  needles.  An  estimation  of  methoxyl-groups 
by  ZeisePs  method  showed  that  the  acid  contains  two  such  groups. 
When  boiled  with  hydriodic  acid,  and  the  product  steam-distilled 
with  zinc-dust,  quinoline  is  obtained. 
In  the  oxidation  of  papaverine  to  papaveraldine,  small  quantities  oi 
the  following  are  formed  besides  dimethoxycinchonic  acid :  a-pyri- 
dinetetracarboxyiic,  veratric,  hemipinic,  and  oxalic  acids,  and  (?) 
meconin. 
Papaveroline,  C16H13N04,  is  prepared  by  boiling  papaverine  with  an 
excess  of  hydriodic  acid.  About  half  of  the  hydriodic  acid  is  then  dis- 
tilled off,  and  the  residue  on  cooling  deposits  crystals  of  the  hydriodide 
of  the  new  base.  This  crystallizes  from  water  in  almost  colorless 
small  needles  with  2  mols.  H20.  The  free  base  is  obtained  by  decom- 
posing the  hydriodide  with  sodium  carbonate  solution  under  a  layer 
of  ether,,  taking  care  to  avoid  an  excess  of  carbonate.  It  forms  white 
crystals  which  soon  become  dark  when  exposed  to  air. 
When  papaverine  is  fused  with  potash  in  a  closed  retort,  dimethyl- 
homopyrocatechol  and  methylamine  distil  over,  whilst  the  residue  is 
found  to  contain  3 : 4  dihydroxybenzoic  acid,  and  a  small  quantity  of 
oxalic  acid. 
The  phenylhydrazine-compound  of  papaveric  acid,  C22H21N306,  crys- 
tallizes in  bright  yellow  needles,  melting  at  190°. 
