Study On Synthesis Of Dibenzofuran And2-ferrocenyl-4H-chromen-4-ones

Many natural products with dibenzofuran framework show good biological activities,they can be used in medicine, dye, disinfectants and preservatives. Meanwhile, dibenzofuranand its derivatives are also important organic synthetic intermediates, they can be used tocomposite heterocyclic compounds and complexes.In this paper, using o-nitrobromobenzene and phenol as the raw materials,2-iodophenylether was prepared by Ullmann cross-coupling reaction, the reduction reaction of nitryl,diazotization reaction and iodination reaction with simple raw material. Using2-iodophenylether as the raw material,5mol%Pd（OAc）₂as catalyst,10mol%PPh3as ligand, K₂CO₃asbase, Bu₄NCl as additive, DMF as solvent, keeping the reaction mixture at150℃for about7h under argon, dibenzofuran was prepared in80%yield.Both chromone and ferrocene have certain biological activities, such as antibacterial,anti-inflammatory, anti-tumor and so on. Put the two compounds together in the synthesis of2-Ferrocenyl-4H-chromen-4-ones, expecting to achieve the sum of activities.In this paper,2-Ferrocenyl-4H-chromen-4-ones was synthesized via carbonylationcoupling-annulation catalyzed by palladium. Ethynylferrocene and2-iodophenol are used asthe starting materials, Pd（PPh₃）/CuI as catalyst, K₂CO₃as base. The reaction is performedunder CO（1atm） to obtain the objective products in good yield. The products arecharacterized by IR,¹H NMR,¹³C NMR, HR-ESI-MS.Antibacterial activities were determined by bacteria inhibiting ring method.Experimental bacteria include Gram negative bacteria （Escherichia coil） and Gram-positivebacteria （Staphylococcus aureus and bacillus）, fungus （Rhizopus nigricans, Aspergillus flavus,Saccharomycetes）. The result shows that2-ferrocenyl-6-methoxy-4H-chromen-4-one has no antibacterial activity, the rest three compounds have good antibacterial activities, there is noobvious antifungal activity observed in experiments.