Diazo compounds of the heterocyclic series. 6. Amination of methoxy-substituted 2-naphthyl- and 2-arylazobenzimidazoles
The amination of azo compounds inactivated by quaternization was carried out for the first time using 4-methoxyphenyl-, 2- and 4-methoxynaphthylazobenzimidazoles as examples. In contrast to the quaternary salts of 2-arylazobenzimidazoles, during the amination of the above bases of azo compounds, the substitution of the methoxy group rather than of the hydrogen atom was observed. The anomalous ease of substitution of the methoxy group, located in the naphthalene ring in a position adjacent to the azo bridge was attributed to the manifestation of an ortho-effect, discovered in the series of azo compounds for the first time.