N-ALKYL-5,6-DIMETHYLBENZIMIDAZOLE-RUTHENIUM (II) CATALYZED N-ALKYLATING REACTION

Abstract

In this study, the new N-coordinated 5,6-dimethyl benzimidazole ruthenium(II) complex was synthesized. Its structure was illuminated by FT-IR, 1H and 13C NMR spectroscopy methods. This complex has been tested for the N-alkylation of aromatic amines with arylmethyl alcohols under neat conditions in the presence of KOBut under solvent-free conditions, at 120 ºC. Compound (2) is stable and have high selective activity for N-alkylation reactions of primary amines to afford secondary amines. It has been found that this complex is effective catalysts for the alkylation of aromatic amines with various alcohols without using solvent. In order to determine the optimum conditions of the catalytic system, we performed the 2 catalyzed N-alkylation of aniline with benzyl alcohol as a model reaction. The results showed us that the optimum conditions were met with 0.025 mmol of catalyst in a solvent-free environment. After that the reactions were performed at a molar ratio of 1:0.025:1 aniline / catalyst / base (S / C / base). It was observed that the catalyst 2 was very active in the reactions using 2-pyridyl amine. Although the conversion is relatively good in reactions using aniline, it was observed that the conversion and yield were quite low in the reactions using 2,4-dimethyl aniline.