Lead as a reducing agent in the preparation of bibenzyls and aromatic azoxy-compounds

Abstract

Lead powder is a convenient reagent for the reduction of aromatic nitro-compounds to the corresponding azoxy-derivatives. Both commercial lead powder and pyrophoric lead prepared from lead acetate and sodium borohydride solutions were effective. Reaction occurs under reflux in dimethylformamide or moist ethanol. Sixteen azoxy-compounds with alkyl, aryl, methoxy-, and halogeno-substituents have been prepared by use of this reagent. The two 2,6-dimethyl-substituted nitrobenzenes examined were reduced to the corresponding anilines. Lead converted benzyl chloride into bibenzyl but none of our specimens of lead were active for the conversion of iodo-benzene into biphenyl which Meszares has effected with another type of pyrophoric lead.