Hindawi Publishing Corporation Journal of Chemistry Volume 2013, Article ID 920130, 6 pages http://dx.doi.org/10.1155/2013/920130 Research Article Evaluation of the Antioxidative Properties of N -Acylamino-Substituted Tricyclic Imides Melek Gul, 1 Irem Kulu, 2 Aysegul Peksel, 2 and Nuket Ocal 2 1 Faculty of Science and Arts, University of Amasya, 05100 Amasya, Turkey 2 Faculty of Science and Arts, Yildiz Technical University, Davutpasa Campus, Esenler, 34220 Istanbul, Turkey Correspondence should be addressed to Irem Kulu; iremkulu@gmail.com Received 25 April 2013; Revised 26 July 2013; Accepted 26 July 2013 Academic Editor: Esteban P. Urriolabeitia Copyright © 2013 Melek Gul et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. New N-acylamino-substituted tricyclic imides have been screened for scavenging ability against the free radical 2,2-diphenyl-1- picryl-hydrazyl (DPPH ∙ ), chelating activity on ferrous ions, and reductive potential. he results were compared with synthetic antioxidants BHT, BHA, and Trolox. he compounds exhibited diferent levels of antioxidant activity in all tests. 1. Introduction N-substituted imides, such as maleimides [1], isohematinic acids [2], and especially bicyclic and tricyclic derivatives such as tandospirone derivatives [3, 4], were found to be remark- able due to variable pharmacological properties, and thus present antibiotic [5], fungicidal [6], analgesic [7], anxiolytic, and cytostatic efects [8]. he imide moiety is an integral structural part of various important bioactive molecules such as fumaramidmycin, granulatimide, isogranulatimide, and rebeccamycin. hese molecules are reported to exhibit antidepressant, antitumor, anti-inlammatory, and antimi- crobial activities [9, 10]. On the other hand, various bicyclic structures such as epiboxidine and epibatidine are biolog- ically important molecules (Figure 1). A literature search reveals that certain compounds with antitumor activity, and in particular molecules able to interact with DNA, are charac- terized by the presence of both an extended -system and an imide function [11–13]. Apart from biological activities, imide derivatives are useful in the reactions involving condensation, alkylation, acylation, and cyclocondensation. Oxidation is essential to many living organisms for the production of energy to fuel biological processes. How- ever, oxygen-centered free radicals or other reactive oxy- gen species (ROS), which are continuously produced in vivo, result in cell death and tissue damage. he role of oxygen radicals has been implicated in several diseases, including cancer, diabetes, cardiovascular diseases, neural disorders, skin irritations, inlammations, and aging [14, 15]. Antioxidants deactivate and scavenge free radicals and inhibit the efect of oxidants by donating hydrogen atom or chelating metals. Synthetic antioxidants such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are used as additives in foods to prevent oxidation of lipids. Besides, BHA and BHT are restricted by legislative rules because of doubts over their toxic and carcinogenic efects [16]. herefore, there is a growing request and interest for safer antioxidants in food and pharmaceutical applications. he Heck reaction, in particular, is widely used as an important method to build biologically active compounds in synthetic chemistry and the pharmaceutical industry [17, 18]. As an extension of the Heck reaction, Pd-catalyzed hydroarylation of alkynes and alkenes continues to attract researchers’ interest in simple coupling processes and cycliza- tion reactions [19, 20]. In the presence of triphenylarsine as a ligand [21, 22] the palladium-catalyzed hydroarylation of the easily accessible, unsaturated tricyclic N-substituted imides such as aryl- and methyl-substituted, epibatidine, epiboxidine, and tandospirone analogs have been proven to be a stereoselective, versatile, and high-yield approach for the synthesis of the corresponding aryl and heteroaryl derivatives [23–31]. Recently, we synthesized N-acylamino-substituted tri- cyclic imides by the palladium-catalyzed hydroarylation