SYNTHESIS, CHARACTERIZATION AND ANTIOXIDANT ACTIVITY OF7-HYDROXY-3',4'-DIMETHOXYFLAVONE

Synthesis of flavones and their derivatives has attracted considerable attention due to their significant pharmaceutical effects. 7-hydroxy-3',4'-dimethoxyflavone has been synthesized and its antioxidant activity has been investigated. Flavone was synthesized by oxidative cyclization of chalcone. 2',4'-dihydroxy-3,4-dimethoxychalcone was prepared by Claisen-Schmidt condensation of 2,4-dihydroxyacetophenones with 3,4-dimethoxybenzaldehydes in the presence of aqueous solution of sodium hydroxide and ethanol at room temperature. Oxidative cyclization of 2',4'-dihydroxy-3,4-dimethoxychalcone was done by using I2 catalyst in DMSO to form 7-hydroxy-3',4'- dimethoxyflavone. The synthesized compounds were characterized by means of their UV-Vis, IR, 1H-NMR and 13C-NMR spectral data. The compound was tested for their antioxidant activities by DPPH method. Keywords: Flavone; chalcone; Claisen-Schmidt condensation; Antioxidant activity Sintesis flavon dan turunannya telah menjadi penelitian yang menarik karena efek farmakologinya. 7-hidroksi- 3',4'-dimetoksiflavon telah disintesis dan diuji aktivitas antioksidannya. Flavon ini disintesis melalui siklisasi oksidatif senyawa kalkon. 2',4'-dihidroksi-3,4-dimetoksikalkon disintesis melalui kondensasi Claisen-Schmidt dari 2,4-dihidroksiasetofenon dengan 3,4-dimetoksibenzaldehid dalam larutan NaOH dan etanol pada suhu ruang. Siklisasi oksidatif 2',4'-dihidroksi-3,4-dimetokskalkon dilakukan menggunakan katalis I2 dalam DMSO untuk membentuk 7-hidroksi-3',4'-dimetoksiflavon. Senyawa hasil sintesis dikarakterisasi berdasarkan data spektrum UV-Vis, IR, 1H-NMR dan 13C-NMR. Senyawa tersebut diuji aktivitas antioksidan menggunakan metode DPPH. Kata Kunci: Flavon; kalkon; kondensasi Claisen-Schmidt; aktivitas antioksidan