Solvent-Free Oxidation under Microwave Irradiation

2 Solvent-Free Oxidation under Microwave Irradiation 

Type of reaction oxidation Reaction condition solvent-free 

Keywords arene, KMn04-alumina, microwave irradiation, aromatic ketone 

Preparation of oxidative system Finely ground potassium permanganate (50 g) dissolved in water (100 mL) was added to alumina (acidic or neutral, Merck activity I, 63-200 nm 200 g). After shaking for 15 min, the majority of the water was removed by evaporation under reduced pressure and the obtained powder was dried under microwave irradiation for 5 min. 

Fluoren-9-one In a Pyrex matrix adapted to a Synthewave 402 monomode reactor, fluorene 1 (2 mmol, 0.332 g) was added to the KMn04-alumina mixture (6 mmol, 4.74 g). After 5 min of mechanical stirring, the mixture was irradiated (under stirring) at 150 W for 10 min. At the end of exposure to microwaves, the mixture was cooled to room temperature and eluted with diethyl ether (50 mL). After filtration and solvent removal, the crude product was identified by comparison (GC and NMR) with an authentic sample. 

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