Transformations of 3-acyl-4H-polyfluorochromen-4-ones under the action of amino acids and biogenic amines

Recent advances in the synthesis of 4H-chromen-4-ones (2012 − 2021)

“…It was found that, for more efficient synthesis of the corresponding 3-acyl-4H-chromen-4-ones, the neutralization step should occur in the presence of a diluted solution of hydrochloric acid followed by treatment with DIPEA in refluxing toluene. 419 When using 3-aryl-3-oxopropanoates as starting materials, after activation of 2-fluoroaroyl chlorides with magnesium methoxide and acidic treatment with diluted hydrochloric acid, the desired methyl 2-aryl-4-oxo-4H-chromen-3carboxylates were obtained in good yields (Scheme 78). 420 One-pot domino Friedel-Crafts acylation/annulation reaction of internal alkynes with 2-methoxyaroyl chlorides in the presence of stoichiometric amount of aluminum bromide in dichloromethane prompted a wide variety of 2,3-disubstituted 4H-chromen-4-ones.…”

Synthesis of Mono- and Polyazole Hybrids Based on Polyfluoroflavones

“…There are known approaches to the synthesis of chromone–azole dyads [ 25 ]; however, data on direct functionalization of fluorine-containing flavones with azoles under S N Ar reaction conditions have only been only in publications from our research team [ 26 , 27 ], although the reaction of nucleophilic aromatic substitution of fluorine atoms is a quite simple, economically and environmentally friendly process, which offers the possibility of substitution for fluorinated substrates with advantages over reactions that use expensive catalysts [ 28 ]. To date, we have considerable practice in the synthesis and modification of polyfluoroflavones [ 26 , 27 , 29 , 30 , 31 , 32 ]. Previously, we proposed a convenient and efficient method for the synthesis of B-ring polyfluorinated flavones (2-(polyfluorophenyl)chromen-4-ones) [ 29 ], which can be involved in S N Ar reactions to obtain polynuclear heterocyclic compounds based on flavones and azoles.…”