Process for preparing substituted diphenyl ethers

摘要

A process for preparing a diphenyl ether of the formula: (I) wherein: X is hydrogen or halogen; Y is hydrogen, halogen, cyano, trifluoromethyl, or an alkyl radical containing 1 to 4 carbon atoms; Z is oxygen or sulfur; R is a methylidene or monosubstituted methylidene, wherein the substituent is selected from the group consisting of alkyl, oxoalkyl and hydroxyalkyl radicals containing from 1 to 4 carbon atoms; and R1 is hydrogen, or an alkyl radical containing from 1 to 8 carbon atoms, a cycloalkyl radical containing from 3 to 8 carbon atoms, an agronomically acceptable cationic salt, phenyl, or mono-, di-, or trisubstituted phenyl, said substituents being selected from the group consisting of halogen, alkyl or alkoxy radicals containing from 1 to 10 carbon atoms, cyano, nitro, and trifluoromethyl; which comprises the sequential steps of: (a) reacting a diphenyl ether of the formula: wherein X and Y are as defined, with an inorganic alkali metal base to form the corresponding acid salt; (b) reacting the acid salt of step (a) with an alpha -halocarboxylic acid ester of the formula: wherein R and Z are as defined; R1 is an alkyl radical containing from 1 to 8 carbon atoms, a cycloalkyl radical containing from 3 to 8 carbon atoms, an agronomically acceptable cationic salt, phenyl, or mono-, di-, or trisubstituted phenyl, said substituents being selected from the group consisting of halogen, alkyl or alkoxy radicals containing from 1 to 10 carbon atoms, cyano, nitro, and trifluoromethyl; and Hal is selected from the group consisting of chlorine, bromine and iodine, to form the corresponding ester; and (c) nitrating the ester product of step (b).