Rapid microwave assisted synthesis and antimicrobial bioevaluation of novel steroidal chalcones

A novel class of chalconoyl pregnenolones has been prepared via Claisen–Schmidt condensation under microwave activation and solvent free reaction conditions. The compounds were screened for antimicrobial activity against two bacterial strains Bacillus subtilis and Escherichia coli and two fungal strains Aspergillus niger and Candida albicans. Some of the compounds exhibited significant inhibitory activity against the microbial strains. Presence of the α,β-unsaturated carbonyl moiety in the synthesized compounds was found to be essential for the activity as manipulation of the same through epoxidation of the double bond diminished the activity.

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► 16 Novel chalconoyl pregenenolones were synthesized.
► A convenient, rapid and solvent free version of Claisen–Schmidt condensation was used for the synthesis of these chalcones.
► Compounds were screened for antibacterial and antifungal activities.
► Compound 9, with a p-F group, was found to be the most active.
► Necessity of the present conformation of the molecule for antimicrobial activities was verified.