SYNTHESIS, CHARACTERIZATION AND ANTIOXIDANT ACTIVITY OF NEW BIS N’-(1H-BENZIMIDAZOL-2-YL)-N-ALKYLAMIDINE DERIVATIVES

Abstract

New series of Bis N’-(1H-benzimidazol-2-yl)-N-alkyl amidine derivatives 2a-e were synthesized starting from (1H-benzimidazol-2-yl) iminoester 1 with two equivalents of ethane-1,2-diamine. The structures of compounds were elucidated by spectroscopic methods including IR, 1 H NMR, 13 C NMR, and 13 C NMR Dept 135° of 2b , elemental analyses and mass spectral analysis. In the next step, the above mentioned compounds were screened for antioxidant activity. Their antioxidant activity was assessed using, the rapid and the most appropriate method, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. The results indicated that bis amidines 2a-e tested possess good antioxidant activity. Compounds 2c and 2e showed excellent antioxidant activity, while compounds 2a , 2d and 2b showed the lowest one. Keywords: Benzimidazole, Bis amidines, DPPH method, ethane-1,2-diamine , Iminoesters.