Synthesis of a series of novel aryl and heteroaryl fused 2,8-dioxabicyclo[3.3.1]nonanes (3) was accomplished by one pot, catalyst free reaction of 2-hydroxy chalcone (1) with 3-trifluoromethyl substituted pyrazolone (2) in xylene at reflux temperature. The role of the trifluoromethyl functional group in formation of 3 was confirmed by comparative studies with 3-methyl substituted pyrazolones (2c,d)
A large series of chalcones were synthesized and studied against Staphylococcus aureus and Escherichia coli. Chalcones were either unsubstituted in ring A or possessed 4-chloro or 3',4',5'-trimethoxy groups. Their other ring B was variously substituted. It was found that the antistaphylococcal activity of chalcones was related to the energy difference between the two highest occupied molecular orbitals (HOMO and HOMO-1). Presence of hydroxyl group in ring B was not a determinant factor for the anti-staphylococcal activity, but the lipophilicity of ring A of the hydroxyl chalcones was of importance. (C) 2008 Elsevier Masson SAS. All rights reserved.