(1) Synthesis of 2′-hydroxy-4′,6′-dimethoxychalcone
Weigh 4.2g of 1,3,5-trimethoxybenzene (0.025mol) and 3.7g of cinnamic acid (0.025mol) into a dry round-bottomed flask, then add 15.0mL of boron trifluoride ether, and condense at 80°C with a drying tube backflow. After 3 hours of reaction, the heating was stopped to room temperature, and red needle-like crystals were precipitated, and the crystals were filtered out. The crystals were added to 100 mL of ethanol aqueous solution and heated under reflux for 2.5 hours to obtain an orange clear liquid, which was decolorized and filtered by adding activated carbon. After cooling, the yellow solid was washed out, filtered, and the washed filter cake was dried to obtain 5.35 g of 2′-hydroxy-4′,6′-dimethoxychalcone, with a yield of 75.4%.
Structural parameters 1H NMR (400 MHz, DMSO-d6), δ: 3.83 (s, 3H, OCH3-4′), 3.91 (s, 3H, OCH3-6′), 6.14 (d, J = 1.6 Hz, 1H, H-3′), 6.17 (d, J = 1.6 Hz, 1H, H-5′), 7.45–7.49 (m, 3H, H-3,4,5), 7.65(d, 1H, J =16 Hz , H-α), 7.72–7.74 (m, 2H, H-2,6), 7.78 (d, J =16 Hz, 1H, H-β), 13.41 (s,1H, OH-2′).
(2) Synthesis of Dim Chrysin
Weigh 5.7g (0.02 mol) of 2′-hydroxy-4′,6′-dimethoxychalcone synthesis, add 30 mL of DMSO to dissolve completely, add 0.13 g of elemental iodine at room temperature, and warm up to 80 °C for reaction 4h hours. After cooling to room temperature, the reaction solution was poured into 200 mL of 2% NaHSO3 solution, and the solid was filtered out after full stirring. After drying, it was recrystallized with absolute ethanol to obtain 4.79 g of Dim Chrysin as pale yellow powdery crystals, with a yield of 84.9%.
Structural parameters 1H NMR (400 MHz, DMSO-d6), δ: 3.83(s, 3H, OCH3-7), 3.90(s, 3H, OCH3-5), 6.50(d, 1H, J=2.4 Hz, H- 8), 6.76(s, 1H, H-3), 6.85(d, 1H, J=2.4 Hz, H-6), 7.56(m, 3H, H-4′,5′,6′), 8.03( m, 2H, H-2′, 3′).
