Theoretical investigation of (−)1-(Benzofuran-2-yl)-2-propylaminopentane [(−)-BPAP] as a hydroxyl radical scavenger Original Research Article

The chemical reactions between (−)-BPAP and radical dotOH were studied using molecular orbital theory, with several simplified models. (−)-BPAP was proved to be a good radical scavenger. It was found that every atom of the benzofuran ring, except carbon 3, was capable of easily trapping the radical, where the most active site was carbon 1 on the furan part. The activation energies for the trappings were ca. 10 kcal/mol by the calculations at UHF/6-31G(d)//UHF/3-21G level. Since the single radical trapping products were still radicals, these could trap further radicals by way of cascade without any activation energy. Thus, the double radical trapping products were very stable, of which the lowest energy level was about 80 kcal/mol lower than the starting reactants.