Chitosan‐Supported Ni particles: An Efficient Nanocatalyst for Direct Amination of Phenols

Abstract

A practical method for the direct amination of phenols using 2,4,6-trichloro-1,3,5-triazine (TCT) as an efficient promotor for the activation of phenols in the presence of an efficient and recyclable heterogeneous catalyst prepared by immobilization of nickel particles on triazole modified chitosan is described.This heterogeneous catalyst has demonstrated a promising activity for the conversion of phenolic compounds to their corresponding amine under mild conditions. Moreover, the obtained catalyst can be reused in five consecutive runs with consistent catalytic activity.

Symmetrical Tertiary Amines: Applications and Synthetic Approaches

“…A similar process for Ph 3 N synthesis from phenol via its modification with trichlorotriazine followed by nickel‐catalyzed coupling was developed by Hajipour and co‐authors in 2018. [ 308 ] This group elaborated a heterogeneous catalyst consisting of nickel nanoparticles stabilized with triazole‐modified chitosan (Scheme 123). This catalyst allowed to couple amines with modified phenols in preparative yields using as low as 0.3 mol‐% of the catalyst.…”

Lignin@Ni‐NPs: A Novel, Highly Efficient, Recyclable, and Selective Nanocatalyst for Base‐Free Transfer Hydrogenation Reactions at Room Temperature

“…Some of the metal nanoparticles (e. g. Pd, Pt, Ag, Au) supported by biopolymers have also been reported to be used as excellent catalysts [3,5] however, biopolymer@Ni‐NPs catalysts used are very scant and the develomnet these would be highly advantageous because it requires highly economic nickel(II) salts and biopolymers [3f–h,9] …”

Nickel-Catalyzed Cross-Coupling of Aryl 2-Pyridyl Ethers with Organozinc Reagents: Removal of the Directing Group via Cleavage of the Carbon–Oxygen Bonds

“…Removing or transforming the OPy unit after directing C–H functionalization will expand the synthetic utility and hence is an important research topic. In recent years, methodologies have been developed to perform the transformations. , For example, Chatani and Feng, respectively, carried out borylation of aryl 2-pyridyl ethers via rhodium-, nickel-, or iron-catalyzed C–OPy bond activation . Zeng et al reported chromium-catalyzed Kumada arylation of aryl 2-pyridyl ethers via C–OPy bond cleavage .…”