Identification of the free radical formed by addition of hydroxyl radical to dehydroalanine compounds.

N-substituted dehydroalanines, a class of compounds with both acceptor and donor substituents (ADs), react with and scavenge oxygen radicals. Interest in these compounds is based on their potential to lessen the cardiotoxicity of drugs with antineoplastic activity such as Adriamycin. The reactivity of these compounds with hydroxyl radical is evident from their inhibition of hydroxyl radical adduct formation. ESR spin trapping studies of the species formed by reaction of the AD series of compounds with the hydroxyl radical are reported here for the first time. ESR results show that hydroxyl radical attack on the capto-dative site of the AD compounds produces the predicted carbon-centered free radical.