Synthesis, characterization and pharmacological screening of some novel 5-imidazopyrazole incorporated polyhydroquinoline derivatives

• The current study is concerned with design and synthesis of novel polyhydroquinoline scaffold.
• The structures of all the synthesized compounds were established on the basis of spectral and analytical data.
• In vitro antimicrobial, antituberculosis and antimalarial activities have been screened for the new compounds.
• Some of these analogs could be worthy candidates for developing new drugs as antibacterial and antimalarial agents.

A new category of polyhydroquinoline derivatives 8a–t were synthesized in moderate to good yield (64–85%) by one-pot three-component cyclocondensation reaction of 5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde 3 with various enaminones 6a–h and different active methylene compounds (malononitrile 7a, ethylcaynoacetate 7b and caynoacetamide 7c) in absolute ethanol. The newly synthesized compounds were evaluated for their in vitro antimalarial activity against Plasmodium falciparum, in vitro antibacterial activity against a panel of pathogenic strains of bacteria and fungi and also for their antitubercular activity against Mycobacterium tuberculosis H37Rv strain. Two of them (8n, 8t) exhibited excellent antimalarial activity. Some of them exhibited excellent antibacterial activity and moderate antituberculosis activity compared with the first line drugs.

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