Click Chemistry with 2-Ethynyl-4,5,6,7-tetrahydroindoles: Towards Functionalized Tetrahydroindole-Triazole Ensembles

Design and synthesis of 5-aryl-4-(4-arylpiperazine-1-carbonyl)-2H-1,2,3-triazole derivatives as colchicine binding site inhibitors

A series of 5-aryl-4-(4-arylpiperazine-1-carbonyl)-2H-1,2,3-triazol derivatives were designed as potential microtubule targeting agents. The regioselective alkylation of 5-aryl-4-(4-arylpiperazine-1-carbonyl)-2H-1,2,3-triazole was predicted by computations and confirmed by an unambiguous synthetic route. The antiproliferative activity of the synthesized compounds was tested in vitro using three human cancer cell lines and some compounds exhibited significant antiproliferative activity, which suggested the reasonability of introduction of the 1,2,3-triazole fragment. Among them, compound 7p showed highest activity with the IC₅₀ values at nanomolar level towards all three cell lines, which were comparable to the positive control, CA-4. Tubulin polymerization assay, immunofluorescence studies, cell cycle analysis and competitive tubulin-binding assay strongly proved that 7p is a colchicine binding site inhibitor of tubulin. Thus, 7p was identified as a promising drug candidate for further development of colchicine binding site inhibitors.