Synthesis of oligoadducts of malonic acid C-60 and their scavenging effects on hydroxyl radical

Seven malonate derivatives of C-60 With different addition number and regio structure were obtained by the "one-pot" reaction of C-60 with diethyl brom omalonate (1:6) and subsequent separation by silica gel chromatography. The corresponding malonic acid derivatives of Cw were formed by hydrolyzing wi th NaH and CH3OH. Four of them with different addition number (C-60(*C(COOH )(2))(n), n = 1-4) were selected to study the scavenging effects on hydroxy l radical. It was shown that these water-soluble C-60 derivatives had scave nging activity and the efficiency was dependent on their concentration and addition number. (C) 2000 Elsevier Science Ltd. All rights reserved.