Stereoselective Photochemistry of Methoxy Chalcones in Solution and Their Radical Scavenging Activity

Abstract

The photochemical dimerization of 3 known methoxy derivatives of chalcones, (2E)-1-(2-methoxy)phenyl-3-phenylpropen-1-one (1), (2E)-1-(3-methoxy)phenyl-3-phenyl-propen-1-one (2), and (2E)-1-(4-methoxy) phenyl-3-phenylpropen-1-one (3), yielded 3 new d -truxinic type dimers in solution: rel-(1b ,2a)- di-(2-methoxy)-benzoyl-rel-(3b ,4a )-diphenylcyclobutane (4), rel-(1b ,2a )-di-(3-methoxy)benzoyl-rel-(3b, 4a )-diphenylcyclobutane (5), and rel-(1b ,2a)- di-(4-methoxy)benzoyl-rel-(3b ,4a )-diphenylcyclobutane (6), stereoselectively. Precursor chalcones showed high superoxide radical scavenging activity although the dimers were inactive.