A  Mar  ST  i9nm' }    Urethanes  of  Thymol  and  Carvacrol.  219 
ously  in  the  flasks.  They  were  heated  for  three-fourths  of  an  hour 
in  the  water  bath.  The  carvacrol  reaction  mixture  became  reddish- 
brown  in  color  and  a  granular  deposit  formed.  The  thymol  mix- 
ture formed  a  mush  of  crystals  that  contained  both  yellow  and 
brown  particles.  These  mixtures  were  extracted  with  heptane  and 
the  residues  washed  with  ether  and  tested  for  hydroxylamine  and 
carbonates.  That  from  the  carvacrol  mixture  gave  a  wholly  nega- 
tive test  with  Fehling's  solution,  but  the  reaction  for  carbonates 
was  positive.  That  from  thymol  gave  positive  reactions  for  both, 
showing  that  the  reaction  was  not  so  nearly  complete  as  in  the  case 
of  carvacrol.  . 
The  ether  and  heptane  extracts  were  crystallized  from  benzene, 
in  which  the  carvacrol  compound  is  very  readily  soluble  and  forms 
spherical  aggregates  of  fine  needles.  The  thymol  compound  is  less 
readily  soluble  and  forms  a  thick  mush  that  was  somewhat  gelatin- 
ous.  Both  are  pale  yellowish  powders  stable  in  the  air. 
Carvacrol  Compound. 
From  benzene  sinters  at  no°,  melts  at  133-136°,  turning  brown. 
From  heptane  sinters  at  no°,  melts  at  1370,  turning  brown. 
Thymol  Compound. 
From  benzene  sinters  at  1450,  melts  at  156-1570,  with  evolution  of  gas.' 
Recrystallized  from  chloroform  sinters  at  1580,  melts  at  158-159°,  with 
decomposition. 
These  two  substances  were  analyzed  for  nitrogen  by  Dumas' 
method : 
Carvacrol  derivative  0.3000  gm.  gave  30.0  cc.  N,  at  25 0  and  708  mm. 
Thymol  derivatice,       0.2556  gm.  gave  17.9  cc.  N2  at  26°  and  707  mm. 
Nitrogen  Found  Calculated  for    Calculated  for 
C1TH1SN203  C10H13NO2 
benzoyl-oxime  nitroso  derivative 
Carvacrol,  10.7  p.'  c.  9.40  p.  c.   
Thymol,  7.5  "    7.82  p.  c. 
It  is  thus  apparent  that  the  benzoyl  derivative  of  carvacrol  re- 
acts to  form  the  oxime ;  while  that  of  thymol  does  not  form  the 
oxime,  but  is  hydrolyzed,  regenerating  the  original  nitrosothymol 
under  the  same  conditions.  This  accounts  for  the- hydroxylamine 
remaining  in  the  residual  salts  of  the  thymol  reaction  mixture. 
Since,  therefore,  the  nitrosocompound  exists,  the  red-brown  color 
with  the  alkalis  is  due  entirely  to  this;  and  carvacrol,  because  it 
