The preparation of certain diphenyl ethers especially 5-(4-trifluoromethylphenoxy)- and 5-(2-halo-4-trifluoromethylphenoxy)-2-nitrobenzoic acid and salts and esters and amides.

摘要

Certain trifluoromethyl substituted diphenyl ethers can be prepared three of herbicidally inactive impurities by a process which comprises:
(A) reacting

to form a compound:

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:

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.