title: 4-N,N-Dimethylaminopyridine promoted selective oxidation of methyl aromatics with molecular oxygen.
abstract: 4-N,N-Dimethylaminopyridine (DMAP) as catalyst in combination with benzyl bromide was developed for the selective oxidation of methyl aromatics. DMAP exhibited higher catalytic activity than other pyridine analogues, such as 4-carboxypyridine, 4-cyanopyridine and pyridine. The sp3 hybrid carbon-hydrogen (C-H) bonds of different methyl aromatics were successfully oxygenated with molecular oxygen. The real catalyst is due to the formation of a pyridine onium salt from the bromide and DMAP. The onium salt was well characterized by NMR and the reaction mechanism was discussed.
authors.affiliation: State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China. zhangzhan@dicp.ac.cn
authors.forename: Zhan
authors.initials: Z
authors.lastname: Zhang
authors.forename: Jin
authors.initials: J
authors.lastname: Gao
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Jie
authors.initials: J
authors.lastname: Xu
mesh_terms: D015761:4-Aminopyridine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D001593:Benzyl Compounds / Q000737:chemistry; D002384:Catalysis / Q000187:drug effects; D019906:Nuclear Magnetic Resonance, Biomolecular; D010084:Oxidation-Reduction / Q000187:drug effects; D010100:Oxygen / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry; D012997:Solvents; D013696:Temperature
chemical_list: D001593:Benzyl Compounds; D011725:Pyridines; D012997:Solvents; D015761:4-Aminopyridine; C023666:pyridine; C003885:4-dimethylaminopyridine; D010100:Oxygen; C038682:benzyl bromide