520 
Quinine  and  Homoquinine. 
Am.  Jour.  Pharm. 
Oct.,  1884. 
Crystals  of  homoquinine  exposed  to  the  air  gradually  become  dull 
through  efflorescence;  in  the  more  compact  crystals,  however,  the 
amount  of  water  never  falls  below  10  per  cent.1  They  can  be  exposed 
directly  to  a  temperature  of  100°  C.  without  any  fear  that  they  will 
fuse,  like,  for  instance,  crystallized  quinine  trihydrate.  At  that 
temperature  the  alkaloid  loses  only  a  portion  of  its  water  of  crystalliza- 
tion ;  it  first  melts  at  170°  C,  forming,  upon  cooling,  a  colorless 
amorphous  mass. 
Homoquinine  dissolves  in  ether  with  somewhat  more  difficulty  than 
quinine;  its  solution  does  not  gelatinize  upon  evaporation  of  the  ether, 
but  crystallizes  up  to  the  last  drops,  if  the  ether  be  absolutely  free 
from  alcohol.  In  chloroform  it  dissolves  readily,  but  with  more  diffi- 
culty in  benzol  and  very  slightly  in  light  petroleum  spirit.  Alcohol 
dissolves  it  freely  and  leaves  it  upon  evaporation  in  the  amorphous 
form. 
The  alcoholic  solution  of  homoquinine  tastes  intensely  bitter  and  has 
a  strongly  basic  reaction  ;  it  neutralizes  hydrochloric  and  sulphuric 
acids  perfectly.  Its  solution  in  an  excess  of  dilute  sulphuric  acid 
shows  a  blue  fluorescence,  which  is  dispelled  by  sodium  chloride  and 
other  haloid  salts.  Hydrochloric  acid  also  removes  this  appearance, 
and  a  solution  of  the  base  in  hydrochloric  acid  shows  no  fluorescence. 
These  solutions  rotate  the  plane  of  polarized  light  to  the  left ;  they 
give  upon  the  addition  of  chlorine  water  or  hypochlorite  of  lime  and 
excess  of  ammonia  a  dark  green  color,  like  quinine. 
With  acids  homoquinine  forms  neutral  and  acid  salts,  which,  so  far 
as  they  have  up  to  the  present  been  examined,  correspond  in  their  be- 
havior towards  precipitants,  such  as  sodium  hydrate  and  carbonate  and 
ammonia,  with  the  corresponding  quinine  salts ;  on  the  other  hand, 
they  differ  from  them  in  their  form  and  partially  in  their  greater 
solubility.  On  account  of  insufficiency  of  material  I  have  only  been 
able  to  deal  at  all  exhaustively  with  the  following  salts  : 
Neutral  Hydrochlorate  of  Homoquinine  is  obtained  by  neutraliza- 
tion of  an  alcoholic  solution  of  the  alkaloid  with  hydrochloric  acid. 
Upon  evaporation  of  this  solution  an  amorphous  residue  is  left  that 
1  The  substance  obtained  in  delicate  lamellae  effloresces  very  rapidly,  and 
frequently  after  a  few  hours  the  quantity  of  water  of  crystallization  amounts 
to  only  about  6  per  cent.  This  phenomenon  may  probably  be  partially  due 
to  the  larger  surface  which  the  lamellae  have  as  compared  with  the  more 
compact  crystals. 
