Cyclization reactions; bischalcones; internal spacer; bispyrazolines; alkyl chains and antimicrobial activity.
The bispyrazolines 3a-3h built around the alkyl chains of varying lengths have been synthesized from the cyclization reactions of bischalcones with phenyl hydrazine. The bischalcones 2a-2h were obtained from the Claisen-Schmidt reactions of acetophenone with various bisaldehydes 1a-1h. The intermediate bischalcones and final bisheterocyclic compounds have been characterized by means of IR, 1H-NMR, 13C-NMR, Mass (ESI) and elemental analysis. The antibacterial and antifungal activities of the synthesized compounds were also evaluated against the Klubsellia pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillius subtilis and Aspergillius janus, Aspergillus niger and Pencillium glabrum, respectively. The antimicrobial behaviour of the bispyrazolines 3a-3h is found to be dependent on the length of internal spacer unit.