Chalcone-based imidazo[2,1-b]thiazole derivatives: synthesis, crystal structure, potent anticancer activity, and computational studies.

In this work, two novel chalcone-based imidazothiazole derivatives ITC-1 and ITC-2 were synthesized and characterized by 1H NMR, 13C NMR and high-resolution mass spectrometry with electrospray ionization, and chemical structure of ITC-1 was confirmed by single-crystal X-ray diffraction. Also, the anticancer activity of ITC-1 and ITC-2 was evaluated. First, antiproliferative activity tests were performed against cancer cells namely, human-derived breast adenocarcinoma (MCF-7), lung carcinoma (A-549), and colorectal adenocarcinoma (HT-29) cell lines, and mouse fibroblast healthy cell line (3T3-L1) by XTT assay. Afterward, mitochondrial membrane disruption (MMP), caspase activity, and apoptosis tests were performed on MCF-7 cells to elucidate the anticancer mechanism of action of the test compounds by flow cytometry analysis. XTT results revealed that both compounds exhibited a very high degree of antiproliferative effects on each tested cancer cell line with very low IC50 values while showing much lower antiproliferation on 3T3-L1 normal cells with much higher IC50 values. Besides, ITC-2 was determined to have a striking cytotoxic power competing with the chemotherapeutic drug carboplatin. Flow cytometry results demonstrated the mitochondrial-mediated apoptotic effects of both compounds through membrane disruption and multi-caspase activation in MCF-7 cells. Finally, molecular docking studies were performed to determine the structural understanding of the test compounds by their interactions on caspase-3 and DNA dodecamer enzymes, respectively. The interactions between the compound and the crystal structure were determined according to parameters such as free binding energies (ΔGBind), Glide score values, and determination of the active binding site. The obtained data suggest that ITC-1 and ITC-2 may be considered remarkable anticancer drug candidates. In addition to molecular docking via in silico approaches, the pharmacokinetic properties of compounds ITC-1 and ITC-2 were calculated using the Schrödinger 2021-2 Qikprop wizard.Communicated by Ramaswamy H. Sarma.

Crystal structures and Hirshfeld surface analyses of 4-benzyl-6-phenyl-4,5-di-hydro-pyridazin-3(2H)-one and methyl 2-[5-(2,6-di-chloro-benz-yl)-6-oxo-3-phenyl-1,4,5,6-tetra-hydropyridazin-1-yl]acetate.

The asymmetric units of the title compounds both contain one nonplanar mol-ecule. In 4-benzyl-6-phenyl-4,5-di-hydro-pyridazin-3(2H)-one, C17H14N2O, (I), the phenyl and pyridazine rings are twisted with respect to each other, making a dihedral angle of 46.69 (9)°; the phenyl ring of the benzyl group is nearly perpendicular to the plane of the pyridazine ring, the dihedral angle being 78.31 (10)°. In methyl 2-[5-(2,6-di-chloro-benz-yl)-6-oxo-3-phenyl-1,4,5,6-tetra-hydropyridazin-1-yl]acetate, C20H16Cl2N2O3, (II), the phenyl and pyridazine rings are twisted with respect to each other, making a dihedral angle of 21.76 (18)°, whereas the phenyl ring of the di-chloro-benzyl group is inclined to the pyridazine ring by 79.61 (19)°. In the crystal structure of (I), pairs of N-H⋯O hydrogen bonds link the mol-ecules into inversion dimers with an R 2 2(8) ring motif. In the crystal structure of (II), C-H⋯O hydrogen bonds generate dimers with R 1 2(7), R 2 2(16) and R 2 2(18) ring motifs. The Hirshfeld surface analyses of compound (I) suggests that the most significant contributions to the crystal packing are by H⋯H (48.2%), C⋯H/H⋯C (29.9%) and O⋯H/H⋯O (8.9%) contacts. For compound (II), H⋯H (34.4%), C⋯H/H⋯C (21.3%) and O⋯H/H⋯O (16.5%) inter-actions are the most important contributions.