Modification of Polyfluoro-Containing 3-(Ethoxycarbonyl)flavones by Biogenic Amines and Amino Acids

Aim and Objective: The objective of our work was to study the peculiarities of transformations of fluorine-containing flavone-3-carboxylates with N-nucleophiles, including biogenic amines and amino acids. Materials and Methods: 6,7,8-Trifluoro and 5,6,7,8-tetrafluoroflavone-3-carboxylates were involved in interactions with a number of N-nucleophiles, such as pyrrolidine, morpholine, proline, arginine, gammaaminobutyric acid, beta-alanine, histamine, dopamine and amantadine under different reaction conditions. All synthesized compounds were characterized by NMR 1H, 19F (NMR 13C for some compounds) and IR spectroscopic data, and elemental analysis. Results: 3-(Ethoxycarbonyl)polyfluoroflavones react with morpholine, pyrrolidine and L-proline to form 7- monosubstituted flavone-3-carboxylates. For the reactions of tetrafluoroflavone with pyrrolidine and morpholine, the formation of 5,7-disubstituted products is also possible. Interaction with gamma-aminobutyric acid leads to the 4-{[3-ethoxy-2-(2-hydroxypolyfluorobenzoyl)-3-oxo-1-phenylprop-1-enyl]amino}butanoic acids as a result of the pyrone ring opening. In reactions with dopamine, histamine, L-arginine and β-alanine, polyfluoroflavone-3-carboxylates underwent a chromone-coumarin rearrangement. 3-(Ethoxycarbonyl)tetrafluoroflavone forms with amantadine the nucleophilic aromatic substitution product, while trifluoro-substituted analog gives the chromone-coumarin rearrangement product. Conclusion: This work showed possibilities of chemical modification of polyfluorinated flavones in the reactions with amines depending on the structure of the nucleophilic reagent. Synthesized compounds are of interest for biological testing.