Flavones were prepared using a one-pot procedure starting from the corresponding 2'-hydroxyacetophenones. The latter were treated with 3 equiv of aroyl chloride in wet K2CO3/acetone (1% w/w water) to afford a good yield of flavone and a smaller amount of 3-aroylflavone. Evidence was obtained that the reaction proceeds via a triketone intermediate. When the reactants were heated in 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and pyridine, the 3-aroylflavone was obtained exclusively. Use of a stoichiometric amount of aroyl chloride afforded only the corresponding flavone. (C) 2011 Elsevier Ltd. All rights reserved.
Using modified Baker–Venkataraman reaction a novel class of 3-acyl flavones and chromones have been synthesised. Reaction mechanism for their formation have been elucidated. The properties of 3-acyl flavonoids indicate them to be precursors for the synthesis of flavones.
The synthesis of new flavone-3-sulfonylurea derivatives is hereby described. The influence of a phenyl group in the 2-position and an acetate group in the 8-position at the chromone nucleus on the activity was studied. Only weak cytostatic activity of the new compounds was found.
A concise synthesis of 3-aroylflavones via Lewis base 9-azajulolidine-catalyzed tandem acyl transfer–cyclization
作者:Masahito Yoshida、Koya Saito、Yuta Fujino、Takayuki Doi
DOI:10.1039/c2cc37015h
日期:——
Lewis base-catalyzed tandem acyl transfer-cyclization of acylated o-alkynoylphenols leading to 3-aroylflavones was developed. 9-Azajulolidine smoothly promoted the reaction of the aroyl derivatives at ambient temperature, and the structure-diversed synthesis of 3-aroylflavones with distinct substituents was achieved in moderate to excellent yields.
syntheses of 3-aroylflavones have been established. In the first synthesis the use of microwave irradiation led to an improvement in the yields of both the Knoevenagel condensation of β-diketones with aldehydes to afford 3-aroylflavanones and of their oxidation to 3-aroylflavones. In the second and more general synthesis, a novel and efficient procedure for 3-aroylflavones involves a one-pot reaction between