Synthesis, Structural Characterization, and Cytotoxic Activity of New Benzo[d]imidazo[2,1-b]thiazole Derivatives Against MCF-7 Breast Cancer Cells

Breast cancer is an invasive disease with a high prevalence among females. Despite various treatments, studies are still ongoing to find an effective treatment for this disease. This study aimed to synthesize a new series of diaryl benzo[d]imidazo[2,1-b]thiazole compounds containing aminoethoxy side chain and in vitro investigate their cytotoxicity on a human breast cancer cell line (MCF-7). Twelve derivatives (6a-6l) were synthesized from this scaffold, the structures of which were spectroscopically confirmed. The cytotoxic effects of the derivatives on the MCF-7 cell line were also assessed using the MTT assay. All these compounds showed a good inhibitory effect on the MCF-7 cell line, compared to that of tamoxifen. Compounds (6i) and (6j) showed higher cytotoxicity with relevant inhibitory effects of 81% and 73%, respectively.

Development of 1,3-thiazole analogues of imidazopyridines as potent positive allosteric modulators of GABAA receptors

Structure-activity relationship studies were conducted in the search for 1,3-thiazole isosteric analogs of imidazopyridine drugs (Zolpidem, Alpidem). Three series of novel γ-aminobutyric acid receptor (GABA_AR) ligands belonging to imidazo[2,1-b]thiazoles, imidazo[2,1-b][1,3,4]thiadiazoles, and benzo[d]imidazo[2,1-b]thiazoles were synthesized and characterized as active agents against GABA_AR benzodiazepine-binding site. In each of these series, potent compounds were discovered using a radioligand competition binding assay. The functional properties of highest-affinity compounds 28 and 37 as GABA_AR positive allosteric modulators (PAMs) were determined by electrophysiological measurements. In vivo studies on zebrafish demonstrated their potential for the further development of anxiolytics. Using the OECD "Fish, Acute Toxicity Test" active compounds were found safe and non-toxic. Structural bases for activity of benzo[d]imidazo[2,1-b]thiazoles were proposed using molecular docking studies. The isosteric replacement of the pyridine nuclei by 1,3-thiazole, 1,3,4-thiadiazole, or 1,3-benzothiazole in the ring-fused imidazole class of GABA_AR PAMs was shown to be promising for the development of novel hypnotics, anxiolytics, anticonvulsants, and sedatives drug-candidates.