140 
Derivatives  of  Santonin. 
/  Am.  Jour.  Pharm. 
I     March,  1886. 
ether,  two  isomeric  photosantonins,  C17H2404,  are  obtained  ;  one  modi- 
fication forms  platy  crystals,  melting  at  154-155°,  and  is  dextro- 
rotatory ;  [a]D=  +*  76*77°  for  a  solution  containing  0*3825  gram  in 
50  c.c.  alcohol  at  13°.  The  other  modification,  which  is  the  chief 
product,  melts  at  68-69°,  and  is  identical  with  Sestini's  photosan- 
tonin.  It  is  readily  soluble  in  alcohol  and  ether,  and  almost  insol- 
uble in  cold  water  ;  [«]D  =  —  121 '6°  for  a  solution  containing  1*0010 
gram  in  50  c.c.  alcohol  at  14°,  and  —  118*4°  for  1*0980  gram  in  50 
c.c.  alcohol  also  at  14°.  The  composition  of  photosantowin  shows 
that  it  is  not  the  diethyl  salt  of  photosantonic  acid  as  Sestini  as- 
sumed, but  the  monethyl-derivative  of  dehydrated  photosan- 
tonic acid,  which  is  regarded  as  a  lactonic  acid,  thus : — Photosan- 
tonic acid,  HO'C13H19(COOH)2;  photosantonic  acid  dried  at  100°, 
COOH*C13H19(co)  ;  photosantonin,  COOEfC13H19(co).  The 
last  compound  may  also  be  obtained  from  photosantonic  acid,  alcohol, 
and  sulphuric  acid,  and  by  the  action  of  ethyl  iodide  on  the  silver  salt. 
When  gaseous  hydrogen  chloride  is  passed  into  a  solution  of  photo- 
santonic acid  in  absolute  alcohol,  the  diethyl-derivative  of  an  acid 
containing  the  elements  of  a  molecule  of  water  less  than  photo- 
santonic acid  is  obtained ;  it  is  termed  ethyl  dehydrophotosantonate, 
C13HlsfCOOEt)2,  and  forms  a  colorless  liquid,  which  does  not  solidify 
at  -  10°.  A  solution  of  0*7306  gram  in  25  c.c.  alcohol  has  a  dextro- 
rotatory power  at  20 "4°,  [«]D  ==  -f  20 "4°.  The  free  acid  which  is 
isomeric  with  dehydrated  photosantonic  acid,  melts  at  132-133°.  It 
is  very  readily  soluble  in  alcohol  and  ether ;  its  dextrorotatory  power 
is  [a]D  =  -f-  319°  for  a  solution  containing  0  7114  gram  in  50  c.c. 
alcohol.  The  barium  salt,  C15Hls04Ba,  is  very  readily  soluble. — Jour. 
Chem.  Soc,  1886,  p.  73;  Berichte  D.  OA.  Ges.,  1885,  pp.  2859-2864. 
Carbon  Disulphide  in  Neuralgia. — Gasparini  (Gazz.  med.  Ital-Lomb.), 
records  1 6  cases  of  neuralgia  treated  with  this  remedy,  applied  locally.  Neuralgias 
from  mechanical  causes,  from  malarial  infection,  and  from  poisoning  by  metals, 
are  not  under  consideration.  The  cases  treated  were  such  as  pure  facial  neural- 
gia, pleurodynia  and  sciatica.  The  method  of  treatment  is  a^  follows :— A  small 
piece  of  cotton  wool  on  which  10-12  drops  of  the  disulphide  have  been  poured  is 
at  once  applied  to  the  painful  spot,  and  covered  with  another  piece  of  cotton 
wool,  which  may  be  held  there  till  the  neuralgia  is  relieved.  The  pain  produced 
by  the  application  is  intense,  and  the  relief  obtained  is  doubtless  from  the  nerve 
affect  d  being  stunned.  In  some  of  the  cases  a  permanent  cure  resulted;  in 
all  there  was  amelioration  of  the  pain. — Med.  Chronicle,  December,  1885,  p.  227. 
