Am.  Jour.  Pharm. 
Sept.,  1893. 
Benzylidine  Dipiperidine. 
431 
sulphide.  The  average  yield  of  the  compound  was  35-38  per  cent., 
while  in  the  experiments  conducted  by  Mr.  Tompkins,  about  40  per 
cent,  was  obtained.  This  amorphous  compound  is  insoluble  in 
alcohol,  but  is  readily  soluble  in  ether,  chloroform  and  disulphide  of 
carbon. 
It  melts  at  a  temperature  of  1 50- 1 5 5  0  C.  and  when  heated  in  small 
quantities  in  test  tubes,  at  a  very  gentle  heat,  fuses  to  a  dark  amber 
colored  liquid,  which  upon  cooling  solidifies  without  crystallization. 
If,  however,  it  be  heated  to  a  higher  temperature,  upon  cooling  it 
deposits  crystals,  part  of  which  are  soluble  in  alcohol  and  the 
remainder  in  ether.  After  removing  the  crystals  soluble  in  alcohol 
and  allowing  to  recrystallize,  the  substance  will  at  first  separate  out 
as  an  amorphous  powder,  which,  however,  after  being  repeatedly 
crystallized  from  chloroform  and  alcohol  may  be  obtained  as  hand- 
some needle-shaped  crystals  or  as  very  fine  crystalline  scales  of  a 
brownish  yellow  color.  That  portion  of  the  crystallized  product 
insoluble  in  alcohol,  but  soluble  in  ether,  was  then  removed  from  the 
amorphous  residue,  and  after  being  repeatedly  crystallized  was 
obtained  in  a  fairly  pure  condition,  when  they  were  found  to  be 
readily  soluble  in  alcohol,  from  which  they  recrystallize  in  handsome 
needles.  These  crystals  have  the  same  melting  point  and  the  same 
properties  as  the  alcoholic  crystals.  They  melt  at  1200  C.  and 
when  analyzed  yielded  the  following  results : 
•  •  -o-6557g  C02 
=  -  0*1788  grams 
C 
.    .    .  0*I220g  H20 
=  0-01355 
H 
.  .  .  o'5232g  CO  2 
===  0-1426  " 
C 
==  0*01112  " 
H 
III.  01280  grams  yielded     .  . 
.  .  .  o-4i79g  C02 
=  0-11397  " 
C 
=  O-0O928  " 
H 
IV.  0*1379  grams  yielded  under  a  barometric  pressure  of  721  mm.  and  at 
a  temperature  of  210  C.  9*8  cc.  of  nitrogen  =  001062768  grams  N. 
Found. 
Calculated  for  C17H30N2  ,  •  , 
Per  Cent.  I.  II.  III.  IV. 
C,  77'8  89*04         85-69         89*03  — 
H,   n*4  670  6*68  7-25  — 
N,  io*6  —  —  —  7*63 
It  is  remarkable  that  this  compound  is  totally  free  from  sulphur, 
which  remains  behind  with  the  amorphous  residue.  Upon  long 
standing  this  amorphous  compound  undergoes  the  same  decomposi- 
tion as  when  heated. 
