Synthesis, Characterization and Antibacterial Activity of some Novel Mannich Derivatives of 3-(Benzofuran-2-Yl)- 1-(4-Hydroxy-3-Methoxyphenyl)Prop-2-En-1-One

Purpose: The present research work is aspired to describe the synthesis, characterization and antibacterial activity of novel Mannich derivatives (4a-4f) derived from apocynin.

Methodology/Approach: In the present work, a novel chalcone was prepared by Claisen-Schmidt condensation of apocynin with benzo[b]furan aldehyde. Mannich bases were prepared by reaction of 3- (benzofuran-2-yl)-1-(4-hydroxy-3-methoxyphenyl)prop-2-en-1-one with formaldehyde and 2° amines.

Findings: All the newly synthesized Mannich base derivatives were characterized by their IR, NMR and Mass spectral data. Further all these final compounds were evaluated for their antibacterial activity using norfloxacin as standard reference. It was observed that among the final derivatives (4a-4f), compounds incorporated with morpholino, piperazino and piperidino moieties (4c-4e) exhibited excellent antibacterial activity, while the compound (4f) with pyyrolidino substituent showed similar promising activity and other compounds (4a-4b) possessed moderate activity.

Original Value: The review of literature revealed that conversion of various acyclic conjugated α,β-unsaturated ketones e.g. chalcones, into the corresponding Mannich bases was often accompanied by increased bioactivity both in vitro and in vivo. These facts prompted us to synthesize novel Mannich base derivatives having better biological activity. All the synthesized compounds were screened for their in vitro antibacterial activity.

Conclusion: The study revealed that compounds (4c), (4d) and (4e) derivatives exhibited highest activity against the tested bacteria.