Highly Dispersed Single-Phase Ni₂P Nanoparticles on N,P-Codoped Porous Carbon for Efficient Synthesis of N-Heterocycles

Abstract

Aerobic oxidative cross-dehydrogenative coupling represents one of the most straightforward and atom-economic methods for construction of C–C and C–X (X = N, O, S, or P) bonds, especially when environmentally friendly air is used as the oxidant. Herein, we report the development of an inexpensive, stable, and highly dispersed ultrafine Ni2P nanoparticles with narrow size distribution supported on N,P-codoped biomass-derived porous carbon. The as-prepared catalyst is highly active and stable for the synthesis of pharmaceutically important N-heterocycles, including quinazolines, quinazolinones, and imidazoles, through oxidative cross-dehydrogenative coupling of a wide range of alcohols with diamines or 2-aminobenzamides using atmospheric air as the sole oxidant under mild reaction conditions. This work provides a new method to access N-heterocycles, which is operationally simple, widely applicable to various alcohols and diamines (or 2-aminobenzamides), and capable for gram-scale synthesis, highlighting its practical potential. Mechanistic studies reveal that the coupling proceeds in a cascade manner, with atmospheric air as a hydrogen acceptor that significantly boosts the overall reaction efficiency.

Type I ‘Lighted Metal‐free’ Photosensitizing Assemblies of Phenazine for Aerobic Oxidative Transformations

“…In literature, the synthesis of 2-substituted quinazolines is reported using the metal complexes and under "metal-free" conditions. [41][42][43][44] Although these reported methodologies are efficient but several shortcomings like use of organic solvents (dioxane, toluene, THF and ethyl acetate) as reaction media, strong oxidants, 'pure' oxygen environment, prolonged heating condition, green LED as irradiation source etc. are yet to Scheme 6.…”

Supported Metal Nanoparticles Assisted Catalysis: A Broad Concept in Functionalization of Ubiquitous C−H Bonds

“…reported an example of a highly dispersed nickel NPs supported on N,P‐codoped porous carbon (Ni 2 P@NPC‐800) catalysed synthesis of N‐heterocycles under atmospheric air and mild reaction conditions (Scheme 21). [36] The as‐prepared catalyst has demonstrated outstanding catalytic activities to afford quinazolines, quinazolinones, and imidazoles via oxidative cross‐dehydrogenative coupling of alcohols and diamines or 2‐aminobenzamides under milder reaction conditions. In addition, high catalytic activity, good functional group tolerance, broad substrate scopes, strong stability, operationally and easy handling was achieved for the synthesis of pharmaceutically important N‐heterocycles.…”

“…With the great advance, considerable recent progress has been achieved in the development of support materials for supported NPs based heterogeneous catalysts. The majority of the support materials are silica [15–21] metal‐oxides [22–30] carbon‐based materials [31–36] and metal‐organic frameworks (MOFs) [37–40] . It has been reported that the catalytic activities of supported metal NPs catalysts can be tuned using a variety of metal‐support interaction types [10,41] .…”

A decennary update on applications of metal nanoparticles (MNPs) in the synthesis of nitrogen- and oxygen-containing heterocyclic scaffolds

“…The Ni 2 P NP-supported biomass-derived N,P co-doped porous carbon (Ni 2 P@NPC-800)-catalyzed cross-dehydrogenative coupling of alcohols (254) with diamines (33a or 6h) or oamino benzamides (133e) was reported for the synthesis of benzimidazoles (84d), quinazolines (32b) and quinazolinones (134c), respectively (Scheme 138). 264 The catalyst was prepared via the hydrothermal and pyrolysis treatment of the biochar of bamboo shoots with Ni(OAc) 2 and phytic acid as Ni and P sources, respectively. The control experiments gave insight into the reaction mechanism, in which the catalyst assists in the oxidation of alcohol to aldehydes and aromatization to the nal compounds.…”