Synthesis, characterization and biological activities of novel chalcone derivatives, containing 4,7-ethanoisoindole-1,3-dione units

Novel chalcone derivatives, containing 4,7-ethanoisoindole-1,3-dione units were synthesized starting from 1,3-cyclohexadine (4) and maleic anhydride (5). Addition of maleic anhydride (5) to 1,3-cyclehexadine (4) gave an endo-adduct, 3a,4,7,7a-tetrahydro-4,7-ethano-2-benzofuran-1,3-dione (6), in 90% yield. Heating the solution of the adduct dione (6) and 1-(4-aminophenyl)ethanone (7) in the presence of Et3N in toluene at 110 oC for 24 hours afforded 2-(4-acetylphenyl)-3a,4,7,7a-tetrahydro-1H-4,7-ethanoisoindole-1,3-dione (8) in high
yield. Piperidine-catalyzed addition of benzaldehyde derivatives (9a-i) to the compound 8 in CH2Cl2 at 55 oC gave the expected chalcone derivatives (10-i) in the range of 42% - 96% yields. The antibacterial activities of the chalcone derivatives (10a-i) were evaluated against human pathogenic microorganism and the compounds showed low activity compared to the standard, name of the standard.