Synthesis of chalcones: Claisen-schmidt reaction

Two chalcone derivatives with D-A substituents were prepared using the Claisen–Schmidt condensation reaction (Scheme 1). The compounds were prepared using a mixture of 1,4-Benzodioxan-6-yl methyl ketone (0.5 mmol, 0.08 g) and anthracene-9-carbaldehyde (0.5 mmol, 0.11 g) for Anth-1, and 9-acetylanthracene (0.5 mmol, 0.11 g) and 2,2’-Bithiophene-5-carbaldehyde (0.5 mmol, 0.09 g) for Anth-2 in methanol with catalytic amount of NaOH (20%, 5 ml). The reaction mixture was stirred for 5–6 h at 25°C and subsequently poured into ice-cold water. The precipitate formed was collected by filtration, and the crude product was purified by repeated recrystallization. Single crystals were grown using the solvent evaporation technique with acetone as the solvent. The yellow, plate-shaped crystals of both compounds are shown in Fig 2.