Certain trifluoromethyl substituted diphenyl ethers can be prepared free of herbicidally inactive impurities by a process which comprises:
to form compound:
wherein X1 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.
某些三
氟甲基取代的
二苯醚可以通过以下工艺制备,其中不含草本活性杂质:
形成化合物:
其中 X1 为卤代,R 为氢、烷基、烯基、炔基、羟基烷基、羧基烷基、烷氧基烷基、
氰基烷基、烷氧基烷基、卤代烷基、碱
金属阳离子、碱土
金属阳离子、季
铵阳离子、
氨基或单-R
氨基或二-R
氨基,和/或 (B) 将(I)与卤化剂反应生成化合物:
其中 X 为卤代,R 如上文所定义。
具有除草活性的化合物(III)可通过
水解作用转化为其他具有除草活性的化合物,其中 R 变成碱
金属阳离子,并进一步反应形成
游离酸。