摘要 |
<p>Certain trifluoromethyl substituted diphenyl ethers can be prepared three of herbicidally inactive impurities by a process which comprises:
(A) reacting
<CHEM>
to form a compound:
<CHEM>
wherein X<1> is halo and R is hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, carboxyalkyl, carbalkoxyalkyl, cyanoalkyl, alkoxyalkyl, haloalkyl, alkali metal cation, alkaline earth metal cation, quaternary ammonium cation, amino or mono-R amino or di-R amino, and/or (B) reacting (I) with a halogenating agent to form a compound:
<CHEM>
wherein X is halo and R is as defined above.
<??>Compounds (III), which are herbicidally active may be converted to other herbicidally active compounds by hydrolysis whereby R becomes alkali metal cation and, further reaction to form the free acid.</p> |