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Cyclodehydration and Baker-Venkataraman Rearrangement Methodologies for the Preparation of Fluorinated 4H-Chromones

Journal: Chemical Methodologies (Vol.4, No. 5)

Publication Date:

Authors : ; ; ; ;

Page : 554-564

Keywords : 1; 3-Diketone; trifluoroacetic anhydride; fluorinated chromone; Solvent-free reaction;

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Abstract

Trifluoromethylated and ring-fluorinated 4H-chromones have been prepared via cyclodehydration and via the baker-venkataraman rearrangement.  The cyclodehydration of 4,4,4-trifluoro-1-(1-naphthol-2-yl)-1,3-butanedione was performed under a variety of base promoted and acid catalyzed processes enroute to 2-trifluoromethyl-β-naphthochromone. Using microwave irradiative, sonication and conventional processes, selected o-hydroxyaromatic ketones underwent single-pot, based promoted baker-venkataraman rearrangements with trifluoroacetic anhydride to give trifluoromethylated 4H-chromones in yields ranging from 50-82%. Microwave irradiation conditions allowed for yields ranging from 50-80%, which compare favorably to yields achieved via conventional methods (60-82%) as well as reducing reaction times by 55% compared to conventional refluxing conditions.

Last modified: 2020-07-07 21:31:48