Development of Aryliminodimagnesium Procedure The Reaction of Nitrobenzene with the Magnesium Reagent Derived from o-Phenylenediaminet

Abstract

For the purpose of developing the synthetic application of aryliminodimagnesium reagent (ArN(MgBr)₂, IDMg), the reactions of ethylmagnesium bromide (EtMgBr) with ami ne hydrochlorides as well as hydroxy- and amino-substituted anilines were examined. Aniline hydrochloride and o-phenylenediamine gave IDMg-type reagent on the treatment with three molar equivalents of EtMgBr.
When the latter reag ent [B] was allowed to react with p-methyl-, p-methoxy-, p-chloro-, and o-hydroxy-nitrobenzenes, o'-amino-azobenzene derivatives were obtained as the major product in 30∼40% yields. The yield of the desired o-aminoazobenzenes was not improved in contrast to the high combined yields of unsymmetrical azoxy- and azo-benzenes obtained previously by the reaction of typical aryl-IDMg and nitrobenzenes. On the basis of the working hypothesis proposed recently for the explanation of the reaction profiles of organomagnesium reagents, the yield distribution of the o-aminoazobenzene and five types of minor products was discussed in terms of the high electron-donating ability of reagent [B] as well as its sterically hindered hisntdruecretudre.