SYNTHESIS OF SOME NEW THIOPHENE-BASED COMPOUNDS AND EVALUATIONS OF THEIR CYTOTOXIC ACTIVITIES

A series of new thiophene derivatives was prepared through nucleophilic substitution reactions of the precursor N-(4-substituted-phenyl)-5-(2-chloroacetamido)-4-cyano-3-methylthiophene-2-carboxamides 4a and 4b with different sulfur and/or nitrogen nucleophilic reagents (namely; mercaptoacetic acid, 2- mercaptobenzothiazole, 5-(phenylamino)-1,3,4-thiadiazole-2-thiol, 2-mercapto-4,6-dimethylnicotinonitrile, 3-arylazo-4-mercapto-4-(phenylamino)-but-3-en-one derivatives, ammonium thiocyanate, piperidine and/or morpholine). The structures of the prepared thiophene compounds were characterized by spectral analysis. Their cytotoxicity was evaluated against two human cancer cell lines (HepG2 and MCF-7) and indicated promising results. Pretreatment of HepG2 cells with the tested compound 4b sensitized the cells to the cytotoxicity of sorafenib, leading to a significant decrease in the IC50 from 3.9 to 0.5 mu M.