Highly reusable support‐free copper(II) complex of para‐hydroxy‐substituted salen: Novel, efficient and versatile catalyst for C─N bond forming reactions

Abstract

An air‐stable, highly active and versatile method for C─N bond forming reactions is reported. Under mild conditions using a highly reusable support‐free Cu(II)–salen complex, structurally diverse N‐aryl‐substituted compounds were obtained via direct C─N bond forming reaction of HN‐heterocycles with aryl iodides or three‐component C─N bond forming reaction of 2‐bromobenzaldehyde, aniline derivatives and sodium azide in good to excellent yields. C─N bond forming reaction for benzimidazole derivatives was also performed in the presence of the catalyst under ambient conditions. A series of hybrid benzimidazoles bearing morpholine, tetrazole and quinoxaline backbones were produced using this method. All reactions were performed in short times under air. The Cu(II) catalyst could be reused up to eight times in the direct cross‐coupling reaction of 9H–carbazole with iodobenzene without any decrease in its catalytic activity.

Preparation, Characterization and Application of Copper Schiff base Complex Supported on MCM‐41 as a Recyclable Catalyst for the Ullmann‐type N‐arylation Reaction

“…A plausible mechanism for the Cu@SB@MCM-41-catalyzed CÀ N bond formation reaction, based on previous reports, [44,47] is proposed in Scheme 2. First, in the presence of base, N-source compound can be coordinated to the metal center by its electron pair.…”

Synthesis of Pharmacologically Active Indazoles and Its Analogues: A Review

“…reported the air stable, onepot multi-component condensation of 2bromobenzaldehyde, primary amine with sodium azide by using a highly reusable support-free Cu(II)salen complex at 120°C to yield 2H-indazole (Scheme 9). 31 We report our attempts to develop C─N bond forming reactions using a mononuclear Cu(II)-salen complex as an inexpensive, efficient and versatile catalyst. This method is a highly active, air-stable, and versatile procedure for C─N bond forming reactions for the synthesis of N-aryl compounds under nearly solvent-free conditions.…”

Green synthesis of shape-tunable CuFe2O4NPs: a magnetically retrievable and efficient catalyst for Chan–Lam type C–N coupling reactions under base-free conditions

“…The C–N bond formation reaction of HN-heterocycles with aryl halides was reported by Sharghi et al by using a highly reusable support-free Cu( ii )-salen complex. 4 The synthesis of N -aryl-substituted compounds was performed via the direct C–N coupling reaction of NH heterocycles with aryl iodide or a three-component reaction between 2-bromobenzaldehyde, aniline derivatives and sodium azide with 81% and 91% yields, respectively. Zarnegar et al explored several heterocyclic and alicyclic compounds for C–N coupling reaction by using amine-modified nano clay via a simple, green and low-cost protocol with very good yield.…”