^b?wyPi92im'  \    Urethanes  of  Thymol  and  Carvacrol.  121 
I.  0.2338  g.  gave  10.9  cc  N2  at  24 0  and  708  mm.> 
II.  o.i9i9g.  gave   8.0  cc  N2  at  240  and  707  mm. 
III.  0.1806  g.  gave    7.4  cc  N2  at  270  and  706  mm. 
Found  Theory  for  C21H21N02 
Nitrogen     I.'   4.77  p.  c.  4.39  p.  c. 
II.    4.48  " 
HI.    4.30  " 
Application  to  Carvacrol. — 2.05  g.  phenol  and  1.55  g.  isocyanate 
were  dissolved  in  15  cc  petroleum  and  heated  exactly  as  for  thymol 
with  much  the  same  results,  except  that  after  the  last  heating  only 
a  faint  covering  of  crystals  on  the  wall  appeared.  By  cooling  in  a 
freezing  mixture  1.05  g.  of  the  crystals  were  recovered.  After  long- 
standing  the  reaction  mixture  had  only  a  thin  covering  on  its  walls. 
The  yield  is  35.9  p.  c.  on  isocyanate  used.  The  melting  point  of 
the  original  crystals  was  1140.  The  first  crop  from  alcohol  melted 
at  1170  to  a  turbid  liquid,  while  the  second  crop  obtained  on  dilution 
melted  to  clear  liquid  at  1190.  It  forms  fine  separate  needles  and 
felted  masses. 
Neuberg  and  Hirschberg  17  claim  to  have  obtained  a  yield  of  43 
per  cent,  of  a  reaction  product  by  heating  carvacrol  and  the  isocya- 
nate together  and  allowing  them  to  react.  It  was  separated  from 
the  by-product  di-  oc  -naphthyl  urea  by  filtration  of  the  acetone  solu- 
tion. They  obtained  needles  melting  at  287-288°,  when  heated 
rapidly.  The  substance  analyses  correctly  for  nitrogen  content  as 
they  found  4.82  p.  c. ;  while  the  calculated  is  4.39  p.  c.  Their  prod- 
uct decomposed  on  slow  heating  and  even  on  keeping.  The  melting 
point  of  di- oc -naphthyl  urea  was  found  to  be  264°.  In  working  up 
the  slightly  soluble  portion  of  the  reaction  mixture  from  hydro- 
thymoquinone,  crystals  were  obtained  melting  at  266-270°,  which 
were  very  likely  the  urea  as  they  appeared  also  in  the  reagent  itself 
when  exposed  to  air,  and  melted  at  264°  from  alcohol. 
Analysis  by  the  Kjeldahl  method,  using  copper  sulphate,  gave 
results  that  were  too  high : 
Analysis  by  Dumas'  method  gave  value  as  recorded. 
Li  0.2016  g.  gave  8.2  cc  N2  at  260  and  708  mm. 
Found  Calculated  for  C21  H^02 
Nitrogen  I.        4.36  p.  c.  4.39  p.  c 
17  Neuberg  and  Hirschberg,  Biochem.  Zeit,  27  (1910),  p.  343. 
