AmlSiF8Tarm"}  Synthesis  of  Active  Conine.  191 
SYNTHESIS  OF  ACTIVE  CONINE. 
By  A.  Ladenburg. 
Further  experiments  on  a  larger  scale,  and  with  pure  materials,  have 
confirmed  the  author's  previous  results  (Am.  Jour.  Pharm.  1886,344). 
a-Allylpyridine  boils  at  187*5 — 192*5°,  and  is  a  strongly  refracting 
liquid  of  sp.  gr.  0*9595  at  0°,  sparingly  soluble  in  water,  and  having 
a  distinct  conyrine-like  odor.  The  platinochloride,  (C3H5.C5H4N)2,H2 
PtCl6,  melts  at  185 — 186°,  and  crystallizes  in  needles  sparingly  solu- 
ble in  water.  The  aurochloride  melts  at  135 — 136°  ;  the  mercurio- 
chloride  and  cadmio-iodide  are  also  described.  By  the  action  of 
sodium  on  an  alcoholic  solution  at  the  boiling  point,  a-allyl  pyridine  is 
reduced  almost  quantitatively  to  a-propylpiperidine.  This  base  has  a 
sp.  gr.  0.8626  at  0°,  and  boils  at  166—167°  ;  its  hydrochloride  crys- 
tallizes in  white,  silky  needles,  melting  at  203 — 205°.  In  smell, 
solubility,  specific  gravity,  and  physiological  action,  a-propylpiperidine 
resembles  conine,  and  not  only  are  the  platinochlorides,  aurochlorides 
and  cadmio-iodides  similar,  but  when  a-propylpiperidine  is  converted 
into  conyrine  by  Hofmann's  method,  a  blue  fluorescence  is  obtained 
just  as  with  conine.  This  fluorescence  is  due  to  an  accompanying  pro- 
duct, for  if  the  fluorescent  base  after  separation  from  unaltered  conine 
be  converted  into  the  platinochloride,  the  conyrine  regenerated  from  it 
is  no  longer  fluorescent.  Conyrine  platinochloride  from  conine  crys- 
tallizes in  monoclinic  forms  :  a  :  b  :  6 >■  ==  l!'06'14  :  1  :  1*5374  ;  ft  = 
87°  8'  •  and  the  crystals  from  the  synthetical  base  give  practically  the 
values  on  measurement. 
a-Propylpiperidine,  however,  in  addition  to  the  lower  melting  point 
of  its  hydrochloride,  is  optically  inactive,  and  must  be  regarded  as  a 
physical  isomeride  of  conine.  To  effect  a  separation  into  two  optically 
active  bases,  a  sterilized  nutritive  solution  containing  0*5  per  cent,  of 
the  tartrate  was  seeded  with  Penicillium  glaucum,  but  without  result. 
The  active  base,  however,  was  obtained  by  introducing  a  crystal  of  the 
salt  into  a  very  concentrated  solution  of  a-propylpiperidine  hydrogen 
tartrate;  a  slow  separation  of  crystals  took  place,  which  yielded  a 
dextrorotatory  base,  whose  specific  rotation  was  [a]D  =  13°87',  corn- 
compared  with  [a]D  =  13°79'  for  conine.  The  hydrochloride  of  the 
synthetical  active  base  melts  at  217*5°,  that  of  conine  at  217*5 — 218*5°. 
From  the  mother-liquor,  a  lsevorotatory  base  was  obtained,  but  it 
contained  a  large  proportion  of  the  dextrorotatory  modification,  which 
could  not  be  further  separated  by  the  crystallization  method.  How- 
