SYNTHESIS AND BIOLOGICAL APPLICATIONS OF SOME NOVEL UREA AND THIOUREA-BENZIMIDAZOLE DERIVATIVES

The objective of this research is the synthesis and characterization of novel urea and thiourea-benzimidazole derivatives and to test their biological activities. The 17 novel compounds (57a-j), (58a-d), 62, 63, and 65 have been synthesized, purified by different techniques such as extraction and column chromatography, and then characterized by using suitable spectroscopic techniques including ¹H-NMR, ¹³C-NMR, fluorescence, and IR spectroscopy techniques. The biological activity of these compounds has been studied. The antibacterial activity was evaluated at different concentrations (μg/ ml) against 6 types of bacteria (Esherichia coli, Pseudomonas aeruginosa, Salmonella enterica, Klebsiella pneumoniae, Staphylococcus aureus and Enterococcus fecalis). Several compounds (57a, 57d, 57e, 57f, 57g, 57h, 57i, 58a, 58b, 58c, 62, 63 and 65) showed activity against enterococcus 29212 and 65 showed activity against p.aereginosa 27853 and s.aureus 25923, with different concentrations ranged 37.4 - 96.3μg/ ml. The antifungal activity of these 17 compounds has been tested against 4 types of fungi (Fusarium solani, botrytis cinerea, thielaviopsis punctulate, and neoscytalidium dimidiatum) and they showed negative results at 250 μM. In the photophysical study, the emission color of compound 65 has been studied through host-guest complexes. The fluorescence of compound 65 was switched from cyan to green upon the addition of cucurbit[7]uril of the prepared compound above by encapsulating the benzimidazole site and then with the 8- hydroxyquinoline site in compound 65. The cyan fluorescence was restored by the addition of cadaverine due to the replacement of the benzimidazole site with cadaverine in the CB7 cavity