Hydroxyl radical scavenging by edaravone derivatives: Efficient scavenging by 3-methyl-1-(pyridin-2-yl)-5-pyrazolone with an intramolecular base

We synthesized various 3-methyl-1-phenyl-5-pyrazolone (edaravone) derivatives and evaluated their oxidation potential and hydroxyl radical scavenging activity. It was found 3-methyl-1-(pyridin-2-yl)-5-pyrazolone had a much higher ability to scavenge the radical than did edaravone itself. Its efficient radical scavenging activity was assumed to be due to the increase of its anion form, an active form, by a hydrogen-bonded intramolecular base.

Graphical abstractThe hydroxyl radical scavenging by pyrazolone derivatives was evaluated, and it was found that 4 was a more efficient derivative than edaravone. It was assumed to be due to the increase of an active form by a hydrogen-bonded intramolecular base.Figure optionsDownload full-size imageDownload as PowerPoint slide