216  Ur ethanes  of  Thymol  and  Carvacrol.  1921.™' 
The  brilliant  color  of  these  products  resembles  that  of  thymo- 
quinone  so  strikingly  that  the  ketone  structure  was  suggested  for 
them 
These  compounds  should  prove  more  useful  for  purposes  of 
identification  of  these  two  phenols  than  the  nitrosocompounds  them- 
selves. These  may  be  derived  from  the  nitrosocompounds  in  one 
step.  They  are  easily  purified,  slightly  sensitive  to  light  and  air  only 
when  moist,  and  are  stable  at  the  melting  point.  The  difference  in 
melting  points  is  220  compared  with  the  difference  of  90  between 
the  nitrosocompounds  which  are  unstable  at  that  point,  and  nitroso- 
thymol  scarcely  has  a  melting  point,  unless  it  has  been  very  carefully 
purified.  It  is  impossible  to  separate  these  compounds,  and  thus 
thymol  and  carvacrol  in  the  presence  of  each  other  cannot  be  distin- 
guished. With  more  stable  compounds  like  the  benzoyl  or  similar 
derivatives  a  separation  may  become  possible.  The  crystalline  forms 
of  the  benzoyl  derivatives  are  strikingly  different  also. 
OXIMES  OF  BENZOYL  DERIVATIVES. 
In  view  of  the  fact  that  the  ketone  structure  has  been  assigned 
arbitrarily  to  these  derivatives,  which  the.  similarity  in  color  with 
thymoquinone  supports,  an  attempt  was  made  to  prepare  an  oxime. 
The  molecular  quantities,  in  one  hundredth  mol,  were  used.  First 
the  alcoholic  solution  of  the  benzoyl  derivative  was  treated  with 
hydroxylamine  hydrochloride  and  potassium  hydroxide, 
Benzoyl  derivative,  2.83  gm.  in  20  cc.  alcohol. 
Hydroxylamine  hydrochloride,         0.7  gm.  in  20  cc.  water. 
Potassium  hydroxide,  .   0.7  gm. 
5  cc.  2N  Potassium  hydroxide  were  used  and  the  mixture  was 
heated  under  a  reflux  condenser  in  a  water  bath  for  three  hours. 
The  orange  solution  in  alcohol  turned  brown  on  addition  of  the 
alkali  and  enough  was  added  to  give  just  such  a  permanent  brown 
color.  The  reaction  mixture  was  poured  into  water  to  dissolve  the 
salt  and  precipitate  the  alcoholic  solution.  The  carvacrol  derivative 
first  gave  an  oil  which  later  solidified  to  a  flocculent  precipitate.  The 
thymol  compound  gave  a  heavy,  flesh-colored  precipitate  at  once. 
The  liquid  smelled  strongly  of  ethyl  benzoate.  The  precipitates 
were  filtered,  washed  and  dried,  and  weighed  and  the  melting  point 
determined. 
