'F2b™£yPi92im' }    Urethanes  of  Thymol  and  Carvacrol.  117 
sented  some  difficulties.  Direct  digestion  with  potassium  sulphate 
yielded  only  very  uncertain  results.  Copper  sulphate  added  as  in 
IV  gave  even  less  satisfactory  results. 
I.  5.5464  g.  required  22.630c  N/10  HCb 
II.  0.5146  g.i  required  13.11  cc  N/10  HQ. 
III.  0.3696  g.i  required  11.72  cc  N/10  HC1. 
IV.  0.2934  g.  required    0.99  cc  N/10  HCL 
Found  Theory  for  Ca7H19N02 
5.20  p.  C.i 
Nitrogen      I.    5.80  p.  c. 
II.    3-35  " 
III.  4-44  " 
IV.  0.4/  " 
On  a  basis  of  yield,  method  of  preparation,  and  melting  point 
determination  the  substance  was  certainly  thymol  phenyl  urethane 
and  the  nitrogen  determination  was  not  checked  by  Dumas'  method 
for  this  compound. 
Application  to  Carvacrol. — 5.04  g.  carvacrol  treated  in  the  same 
was  as  thymol  and  run  in  parallel  yielded  7.77  g.  urethane,  or  86 
per  cent.  This  melted  originally  at  134.5°  to  136°.  Crystallized 
from  alcohol  (95  per  cent.)  is  melted  at  1380.  Further  crystalliza- 
tion from  alcohol  did  not  raise  this  value.  The  hot  benzene  solu- 
tion sets  to  a  mush  on  cooling  and  the  product  melted  at  133.5  to 
134.50.  Addition  of  an  equal  volume  of  heptane  to  these  mother- 
liquors  gave  a  copious  deposit  of  crystals  melting  this  time  at  138°. 
It  was  found  impossible  to  raise  the  melting  point  to  140°,  as 
has  been  claimed  by  Gildemeister  15  for  this  substance ;  even  though 
it  had  been  treated  with  the  following  solvents :  alcohol,  dilute  alco- 
hol, benzene  and  heptane. 
Analysis  by  the  Kjeldahl  method  using  potassium  sulphate  and 
also  with  copper  sulphate  as  in  IV  gave  unsatisfactory  results. 
In  order  to  confirm  the  composition  of  these  substances  nitrogen 
was  determined  by  the  Dumas  method. 
I.  0.3054  g.  yielded  14.9  cc  nitrogen  at  22°  and  701  mm. 
II.  0.2440  g.  yielded  13.5  cc  nitrogen  at  240  and  703  mm. 
Found  Theory 
I.  5.25  p.  c.i  5.20  p.  c. 
II.  5-53  "  . 
15  Gildemeister,  Arch.  d.  Pharm.,  233  (1895),  pj  188. 
