Background: In the present study chalcones were synthesized from 2-hydroxy-1-acetonaphthone and substituted aromatic aldehydes by Claisen Schmidt condensation reaction using potassium hydroxide as a base. The synthesized chalcones were purified by recrystallisation from ethanol and evaluated for antibacterial activity by well diffusion method. The antibacterial activity was evaluated against Bacillus licheniformis, Bacillus species, Escherichia coli and Staphylococcus aureus using Ciprofloxacin as a standard.
Method: The target molecules were prepared by reacting 2-hydroxy-1-acetonaphthone and various substituted aromatic aldehyde in the presence of suitable condensing agents. The structure of synthesized compounds were confirmed on the basis of elemental analysis, IR, 1H NMR and 13C NMR spectral data. These synthesized compounds also screened for antibacterial activity.
Results: In the present study free hydroxyl group in position 2 or 4 of aldehyde ring of synthesized chalcones appears to be a very important requirement in increasing the activity (2-5 and 8-13). When the hydroxyl group in position 4 is alkylated (14, 15) the chalcones are not more active. When more complex substituent on aldehyde ring (6, 7) there is a decrease in the activity.
Conclusion: Newly synthesized chalcones (1-15) shows good and moderate antibacterial activity, we believe that the new hydroxy substituted (in aldehyde ring) chalcones (2-5 and 8-13) reported in this work may provide an interesting insight for further optimization.