The First Case of an Aryl Imination Reaction by Direct Nucleophilic Substitution of Hydrogen: Synthesis of 2-arylimino Derivatives for 1,2-dihydro-1-methyl-5(6,7,8)-nitroquinolines

Abstract

The oxidative SNH aryl imination of 1-methyl nitro quinolinium salts is described. The first 2-arylimino derivatives of 1,2-dihydro-1-methyl-5(6,7,8)-nitroquinolines have been synthesized in a one-step reaction (ONSH process) under mild conditions and without preliminary introduction of a leaving group. The resulting products are stable and cannot be obtained via direct interaction of anilines with the corresponding quinolones. The approach found is interesting due to its simplicity of implementation, since the reaction involves the nucleophilic addition of anilines induced by the base, followed by the oxidation of the σH adducts occurring in one pot. This article discusses the synthesis conditions and optimization procedures. We also noted the influence of the position of the nitro group on the reaction yield. A possible reaction mechanism is proposed, supported by the detection of an intermediate product using an NMR experiment. The method's simplicity and retaining the nitro group in the final product offer considerable potential for further structural diversification.