The Co2+ Complex of [7-Hydroxy-4-methyl-8-coumarinyl]glycine as a Nanocatalyst for the Synthesis and Biological Evaluation of New Mannich Bases of Benzimidazoles and Benzothiazoles

In this paper, a series of novel Mannich bases of benzimidazoles and benzothiazoles were synthesized via a one-pot two steps reaction of 1,2-phenylenediamines or 2-aminothiophenols with several in situ synthesized Mannich bases of aldehydes in the presence of nanostructured Co2+ complex of [7-hydroxy-4-methyl-8-coumarinyl]glycine ([Co(MCG)(H2O)(3)] as a reusable and bioactive catalyst. To the best of our knowledge, it is the first report on the application of nanostructured coumarin-based metal complexes [M(MCG)(H2O)(3)] for the synthesis of organic compounds. The nanostructured coumarin-based cobalt complex as a catalyst could be reused up to six times without a decrease in its catalytic activity. The cytotoxic activities of synthesized benzimidazoles were investigated against the colon cancer cell line (HT-29) and fibroblasts cell lines (HFF) as a non-cancerous cell line, at 24 and 72 hours after incubation using 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium (MTT) assay.