Synthesis of new flavonoid derivatives based on 3-hydroxy-4′-dimethylamino flavone and study the activity of some of them as antifungal

Chalcone was prepared in a new route by reacting o-hydroxyacetophenone with 4-dimethylaminobenzaldehyde using piperidine as a catalyst. 3-Hydroxy-2-[4-(dimethylamino)phenyl] benzopyran-4-one were prepared by Algar-Flynn-Oyamada method by cyclization of chalcone using Hydrogen peroxide. A series of alkyl and ester derivatives of the flavonoid 3-hydroxy-2-[4-(dimethylamino)phenyl] benzopyran-4-one were prepared by reacting the above mentioned compound with different chemical reagents (Methyl iodide, Allyl bromide, Benzyl chloride, Bromoacetylcoumarin, Chloroacetamide, Chloroacetyl chloride, Phthalic anhydride, Maleic anhydride, Phthalimide, Cinnamoyl chloride) with potassium carbonate and acetone or DMF as a solvent. The physical and spectroscopic properties of the new compounds were studied by (FT-IR, 13C-NMR and 1H-NMR) spectral methods. The purity of the synthesized compounds were confirmed using TLC thin layer chromatography. The biological activity of some synthetic flavonoids (A2, A5, A7, A8, A9, A12) at two different concentrations (0.5 mg/ml, 0.25 mg/ml) were studied on three types of fungi: Aspergillus flavus, Acremonium strictum, Penicillium expansum. Some of this compounds showed high activity against the tested fungi. Aldol condensation; Oxidative cyclization; Chalcone; Flavonol; o-Alkyl flavone; Bromo-acetylcoumarin; Antifungal.