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Palladium‐Based Catalysts Supported by Unsymmetrical XYC –1 Type Pincer Ligands: C5 Arylation of Imidazoles and Synthesis of Octinoxate Utilizing the Mizoroki–Heck Reaction
Author(s) -
Maji Ankur,
Singh Ovender,
Singh Sain,
Mohanty Aurobinda,
Maji Pradip K.,
Ghosh Kaushik
Publication year - 2020
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.202000211
Subject(s) - chemistry , morpholine , catalysis , aryl , aniline , methyl acrylate , medicinal chemistry , ethyl acrylate , pyridine , aryl halide , pincer movement , heck reaction , palladium , polymer chemistry , organic chemistry , acrylate , copolymer , alkyl , polymer
A series of new unsymmetrical (XYC –1 type) palladacycles ( C1 – C4 ) were designed and synthesized with simple anchoring ligands L 1–4 H (L 1 H = 2‐((2‐(4‐methoxybenzylidene)‐1‐phenylhydrazinyl)methyl)pyridine, L 2 H = N,N‐dimethyl‐4‐((2‐phenyl‐2‐(pyridin‐2‐ylmethyl)hydrazono)methyl)aniline, L 3 H = N,N‐diethyl‐4‐((2‐phenyl‐2‐(pyridin‐2‐ylmethyl)hydrazono)methyl) aniline and L 4 H = 4‐(4‐((2‐phenyl‐2‐(pyridin‐2‐ylmethyl)hydrazono) methyl)phenyl)morpholine H = dissociable proton). Molecular structure of catalysts ( C1 – C4 ) were further established by single X‐ray crystallographic studies. The catalytic performance of palladacycles ( C1 – C4 ) was explored with the direct Csp 2 –H arylation of imidazoles with aryl halide derivatives. These palladacycles were also applied for investigating of Mizoroki–Heck reactions with aryl halides and acrylate derivatives. During catalytic cycle in situ generated Pd(0) nanoparticles were characterized by XPS, SEM and TEM analysis and possible reaction pathways were proposed. The catalyst was employed as a pre‐catalyst for the gram‐scale synthesis of octinoxate, which is utilized as a UV‐B sunscreen agent.