656 
Chemistry  of  Gossypol. 
Am.  Jour.  Pharm. 
Sept.,  1918. 
gossypol  after  removing  the  acetic  acid  of  combination.  The  free 
gossypol  left  after  removal  of  the  acetic  acid  in  the  above  determi- 
nations was  dissolved  in  alcohol  and  titrated  with  alkali,  using  phe- 
noltetrachlorophthalein  as  indicator.  Since  the  gossypol  solution 
is  yellow  the  end  point  is  more  difficult  to  detect. 
The  weights  of  gossypol  used  here  were  found  by  subtracting 
the  10.12  per  cent,  and  10.17  per  cent,  acetic  acid  from  the  weights 
of  the  gossypol  "  acetate  "  used  above. 
Subst,  (I)  0.4787,  (II)  0.4543;  Cc.  0.1  N  NaOH,  (I)  17.6,  (II)  17.0. 
Hence  assuming  gossypol  neutralizes  two  equivalents  of  NaOH 
the  values  for  the  molecular  weight  are  (I)  544,  (II)  532. 
Concordant  results  were  also  obtained  by  titrating  weighed 
amounts  of  pure  gossypol  and  of  gossypol  "  acetate."  The  "  ace- 
tate," as  is  evident,  neutralizes  three  equivalents  of  alkali.  While 
gossypol  thus  behaves  as  a  fairly  strong  acid,  it  is  not  thought  that 
it  contains  carboxyl  groups  since  the  benzoyl  and  acetyl  derivatives 
are  not  soluble  in  cold  dilute  aqueous  alkali.  The  fact  that  the 
disodium  salt  of  gossypol  is  neutral  to  phenolphthalein  in  aqueous 
solution  gives  an  indication  of  its  relative  strength  as  an  organic  acid. 
Empirical  Formula. — The  following  analytical  data  give  results 
which  agree  well  with  the  formulas  C30H28O9  or  C30H30O9  for 
gossypol. 
Analysis  of  Gossypol  "  Acetate  "  Four  Times  Recrystallized  from  Ether 
and  Glacial  Acetic  Acid. 
Subst. 
C02. 
H20. 
%c. 
%H. 
1st  Crop  c 
/  Crystals. 
O.2321 
0-5547 
0.1197 
65.16 
5-77 
O.2263 
0.5404 
0.1197 
65.12 
5-92 
2d  Crop  0 
/  Crystals. 
3  
0.2107 
0.5013 
0.1089 
64.89 
5-79 
4  
0.2161 
0.5142 
O.1072 
64.89 
5-55 
5  
0.2182 
0.5205 
O.H53 
65-04 
5-9i 
Calc.  for  C30H28O9.C2H4O2: 
64.84 
5-45 
Calc.  for  C30H30O9.C2H4C2: 
64.62 
5-77 
Analyses  of  other  Pure  Preparations  of  Gossypol  "Acetate." 
0.1943 
0.4628 
O.0963 
64  94 
5-55 
0.2207 
0.5257 
0.1080 
6497 
5-48 
3  •  
0.2022 
0.4819 
O.0989 
6498 
5-47 
