Oxidative stress has been implicated in the development of many neurodegenerative diseases such as Parkinson and Alzhemier's disease and is also responsible for aging, artherosclerosis, rheumatoid arthritis and carcinogenesis. Olefins such as dehydroalanines have been shown to inactivate free radicals by forming stabilized free radical adducts. Among these molecules N-acyl dehydroalanines react with and scavenge oxygen and hydroxyl radicals. This study describes the synthesis, characterization and in vitro effects on rat liver lipid peroxidation levels, and DPPH free radical scavenging activities of some N-acyl dehydroalanine derivatives. Compounds c, f and j slightly scavenged the level of DPPH radical at 10(-3) M concentration by about 27, 46, and 56%, respectively while compounds a, d, e, f, g, h showed a strong inhibitory effect on lipid peroxidation at 10(-3)M and 10(-4)M concentrations and inhibition was in the range of 76-90%. The possible antioxidant mechanism of the compounds was discussed.