Design, synthesis, and biological evaluation of 1,4,7,8‐tetrahydro‐5H‐furo[3,4‐b]pyrazolo[4,3‐e]pyridin‐5‐one‐based azo dyes.

Some 1,4,7,8‐tetrahydro‐5H‐furo[3,4‐b]pyrazolo[4,3‐e]pyridin‐5‐ones containing azo group were synthesized by a three‐component one‐pot reaction of a preformed azoaldehyde (AZA), tetronic acid, and 5‐aminopyrazole in ethanol in the presence of triethylamine under microwave irradiation. The structures of the products were confirmed by spectroscopic data. This method has the advantages of simpler operation to prepare a new dihydropyridines (1,4‐DHPs) ring with multi‐functional groups architecture, high efficiency, short reaction time, and exciting atom economical chemistry. All the products were evaluated regarding antibacterial activities. Some compounds exhibited potent antibacterial activity against both Gram‐negative (Escherichia coli) and Gram‐positive (Micrococcus luteus and Staphylococcus aureus) bacteria compared with erythromycin and tetracycline. The antioxidant activity (AOA) of the synthesized compounds was considered in comparison to vitamin C. Some compounds exhibited the highest AOA, even higher than vitamin C. [ABSTRACT FROM AUTHOR]