The preparation of a Co@C₃N₄ catalyst and applications in the synthesis of quinolines from 2-aminobenzyl alcohols with ketones

Abstract

The unsymmetrical diphenylphosphino-pyridinyl-triazole ligand was synthesized and characterized through IR, NMR and MS and the corresponding earth-abundant metal complex (cobalt) was prepared. Considering energy consumption and environmental friendliness, it is...

Schiff‐base Polymer Immobilized Ruthenium for Efficient Catalytic Cross‐coupling of Secondary Alcohols with 2‐amino‐ and γ‐aminobenzyl Alcohols to Give Quinolines and Pyridines

“…The optimal reaction time was 24 h (entries 13-14). No reaction occured in the absence of catalyst, with polymer alone, or with RuCl 3 • xH 2 O (entries [15][16][17]. The amount of the RuCl 3 loading was evaluated.…”

“…However, these homogeneous molecular catalysts have not been widely used after their initial reports because of complicated syntheses, recycling problems and potential metal contamination of the products [11] . Heterogeneous metal nanoparticles (NPs) supported on silica–based materials, [12] metal oxides, [13] magnetic nanoparticles, [1d] metal–organic frameworks (MOFs), [14] polymers, [11a] and carbon nitride (g‐C 3 N 4 ) [15] have been developed as catalysts for the assembly of quinolines by ADC and auto–transfer–hydrogen (ATH) methods. However, heterogeneous catalysts generally have lower activity and structures that make ligand cooperative catalysis difficult to achieve.…”

Accessing 2‐Aryl Quinolines via Acceptorless Dehydrogenation and Transfer Hydrogenation Under Base and Solvent‐Free Reaction Conditions

“…In the last decade, acceptorless dehydrogenation, borrowing hydrogen, and transfer hydrogenation strategies have gained popularity to overcome these challenges [15,16] . Owing to this, there are numerous reports on acceptorless dehydrogenative synthesis of quinolines utilizing homogenous catalytic system involving metals such as Co, [17] Cu, [18] Ir, [19] Fe, [20] Mn, [21] Ni, [22] Re, [23] Ru, [24] Zn, [25] and heterogeneous catalyst such as Co on C 3 N 4 , [26] CuO, [27] CuNiFeO, [28] Fe 2 O 3 , [29] CoFe 2 O 4 , [30] Ir on mesoporous silica, [31a] porous organic polymer supported Ir catalyst, [31b] covalent triazine framework supported Ir complex, [31c] Pd on polymer support [32] . However, the synthesis of quinoline via transfer hydrogenation strategy remains less explored [33–36] .…”