Efficient synthesis of α-Nitro-β-Dialdimine ligands via Equilibrium-Controlling approach

Reactions of beta-formyl-beta-nitroenamine with anilines afforded N,N'-diaryl-alpha-nitro-beta-dialdimines; however, only small amounts of dialdimines were obtained when anilines possessing an electron-withdrawing group were employed. This disadvantage was overcome by adding anilinium salts to control the equilibrium, which resulted in the formation of dialdimines in considerably improved yields. This method facilitated to introduce less nucleophilic 5-bromopyrid-2-yl groups that are expected to be a precursor for various frameworks. The prepared dialdimines served as a ligand which formed the nickel(II) complex with a distorted tetrahedral structure. (C) 2022 Elsevier Ltd. All rights reserved.

Automated summary

The addition of anilinium salts to the reaction mixture significantly improved the yield of N,N'-diaryl-alpha-nitro-beta-dialdimines formed from the reaction of beta-formyl-beta-nitroenamine with anilines, allowing the introduction of less nucleophilic substituents.