Synthesis and evaluation of phenyl substituted sydnones as potential DPPH-radical scavengers

Abstract

A series of phenyl substituted sydnones has been synthesized and their radical-scavenging activity has been studied on DPPH free radical. Out of eighteen compounds screened, nine compounds show interesting activity. A mechanism is presented whereby sydnones scavenge DPPH radical through donating H-atom at 4th-position. Its strong radical-scavenging activity mainly arises from 1, 2, 3-oxadiazolium-5-olate ring. Different substituents and their positions on the phenyl ring differently influence DPPH scavenging activity and therefore, may provide clues to design and develop better free-radical scavenging sydnones with multiple activities.