Easy synthetic approach to p-aminophenoxy derivatives bearing phosphonic or carboxylic ethyl ester groups

Condensation of the ethyl esters of phenyl carboxylic acids or phenyl-phosphonic acids with halonitrobenzenes in anhydrous acetonitrile in presence of potassium carbonate produces 4'-nitrophenoxy-benzoic or benzo-phosphonic acid ethyl esters in good yields. This procedure, which represents a new approach for the nucleophilic condensation, is particularly useful for substrates bearing ancillary reactive groups for which the usual procedure described in literature leads to decomposition products. Reduction of the parent nitro derivatives by hydrazine in the presence of palladium catalyst yields the corresponding amines in very high yield.