120  Ur ethanes  of  Thymol  and  Carvacrol.  {^iJuSyPi92im' 
The  product  is  thus  practically  pure  as  it  separates  from  the 
reaction  mixture.  After  extraction  of  the  crystals  with  benzene  to 
remove  solvent  they  may  be  obtained  pure  by  one  crystallization 
from  acetone  or  two  from  ethyl  acetate. 
oc-NAPTHYL  URETHANES. 
In  the  extension  of  this  work  to  the  use  of  oc-napthyl  isocya- 
nate  as  a  reagent  the  method  of  Weehuizen  was  used.  There  is  one 
mention  of  the  preparation  of  the  carvacrol  derivative.  The  same 
procedure  was  followed  as  in  the  other  cases,  for  the  phenol  and 
isocyanate  were  heated  together  with  petroleum  in  an  acetylation 
flask.  The  yields  with  this  reagent  were  not  so  good.  Perhaps  a 
greater  solubility  in  the  petroleum  accounts  for  this  because  after 
separation  of  one  crop  of  crystals  and  reheating  only  a  very  little 
more  came  down.  With  phenyl  isocyanate  the  intensity  of  the  odor 
was  a  gauge  of  the  completeness  of  the  reaction,  but  that  advantage 
was  lost  here.  To  conserve  the  reagent  the  phenols  were  taken  in 
slight  excess  in  these  reactions. 
Application  to  Thymol. — 2.00  g.  thymol  and  1.65  g.  isocyanate 
were  heated  with  15  cc  petroleum  for  45  minutes.  On  standing 
over  night  nothing  crystallized  out  even  on  scratching  the  walls  of 
the  flask.  It  was  again  heated  for  one  hour  and  fifty  minutes  after 
which  crystals  appeared  on  cooling.  The  crystals  appeared  as  radi- 
ating clusters  or  spherules  and  weighed  1.34  g.,  melting  at  155°. 
The  first  crop  from  alcohol  came  out  as  clusters  of  needles,  melting 
at  1 56- 1 570;  while  a  further  quantity  recovered  by  dilution  of  the 
alcohol  melted  at  149-150.50.  On  long  standing  the  reaction  mixture 
deposited  a  slight  crust  on  the  walls  of  the  container  The  yield  is 
43.0  p.  c.  From  alcohol  it  forms  felted  masses  of  needle-like  crys- 
tals, melting  at  156-1570. 
After  the  reaction  mixture  had  been  heated  again  and  allowed 
to  stand  four  weeks,  only  a  very  thin  crust  of  crystals  on  the  walls 
of  the  flask  appeared. 
An  analysis  of  this  compound  by  the  Kjeldahl  method,  using 
copper  sulphate,  gave  unsatisfactory  results.  Analysis  by  Dumas' 
method  gave  results  agreeing  with  the  theory. 
