Synthesis of Isoxazolopyridines and Spirooxindoles under Ultrasonic Irradiation and Evaluation of Their Antioxidant Activity

Abstract

New polycyclic-fused isoxazolo [4,5-e]pyridines and spirooxindoles were obtained via multicomponent reaction of 5-amino-3-methylisoxazole, indan-1,3-dione, and aromatic aldehydes and reaction of 5-amino-3-methylisoxazole, isatin, and -diketones in the presence of (±)-camphor-10-sulfonic acid as an effective and nontoxic organocatalyst under ultrasound-promoted conditions. The antioxidant activity of the novel synthesized compounds was studied.

The application of isatin-based multicomponent-reactions in the quest for new bioactive and druglike molecules

“…The antioxidant activity of these compounds was evaluated, using the DPPH radical scavenging assay, metal chelating activity and reducing power. Unfortunately, the results were poorer than those obtained with the reference compounds [148].…”

Spirocyclic derivatives as antioxidants: a review

“…Compounds D27 and D28 at a concentration of 400 μg mL −1 presented percentages of DPPH radical scavenging of 55 and 58% and were compared with BHA as a positive control that at the same concentration manifested a percentage of scavenging of 99%. 121 …”