Ultrasound-assisted one-pot four-component synthesis of novel 2-amino-3-cyanopyridine derivatives bearing 5-imidazopyrazole scaffold and their biological broadcast

• 2-Amino-3-cyanopyridine incorporated 5-imidazopyrazole analogs was designed.
• All the compounds were synthesized using ultrasonic irradiation.
• Targeted compounds were identified by spectroscopic methods.
• Designed compounds were screened for their biological evaluation.
• SAR study was briefly discussed.

An alternative and environmentally caring way for the synthesis of novel 2-amino-3-cyanopyridine derivatives bearing 5-imidazopyrazole nucleus is reported by one-pot four-component cyclocondensation reaction of substituted 5-(1H-imidazol/4-methyl-1-yl)-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde (3a–b), malononitrile (4), ammonium acetate (5) and aromatic (6a–f)/heterocyclic methyl ketones (7a–d) under ultrasonic irradiation. The newly synthesized compounds were evaluated for their in vitro antibacterial activity against a panel of pathogenic stains of bacteria and fungi, in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv stain and in vitro antioxidant activity by ferric-reducing antioxidant power method. Compounds 8e, 8h, 8l, 9c, 9g and 9h exhibited excellent antibacterial activity and compounds 3a, 8k, 9a and 9bshowed moderate antituberculosis activity as compared with the first line drugs. Majority of the compounds showed excellent antioxidant activity. This approaches claimed to be an environment friendly protocol as it afforded numerous advantages i.e. excellent yields, cleaner reaction profile and shorter reaction time.

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