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Sonochemical Preparation of Dipicolinamide Mn‐complexes and Their Application as Catalysts Towards Sono‐synthesis of Ketones
Author(s) -
Arafa Wael A. A.
Publication year - 2019
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.3518
Subject(s) - chemistry , catalysis , hydrogen peroxide , manganese , picolinic acid , acetic acid , sonication , condensation , acetic anhydride , hydrogen chloride , organic chemistry , condensation reaction , chloride , physics , chromatography , thermodynamics
A series of non‐heme Mn‐complexes has been synthesized by the sonication of manganese (II)chloride and bis‐amides (condensation products of 2‐picolinic acid and o ‐phenylenediamines). The Mn‐complexes effectively promote the oxidation of unactivated aliphatic and benzylic C─H and N ‐bearing heterocycles substrates with low catalyst loading using eco‐friendly hydrogen peroxide in the presence of acetic acid as additive under ultrasonic irradiation. Chromatographic studies revealed that the corresponding ketones are the only detectable products. Noteworthy, the presence of electron donors in the catalyst structure significantly increased the reaction yields. The substantial lowering of the oxidation reaction yields by adding ionol (2,6‐di‐ tert ‐butyl‐4‐methylphenol) as a free radical trap suggesting a free radical reaction pathway.