Insight into the inhibitory potential of metal complexes supported by (E)-2-morpholino-N-(thiophen-2-ylmethylene)ethanamine: synthesis, structural properties, biological evaluation and docking studies

A thiophene-derived Schiff base ligand (E)-2-morpholino-N-(thiophen-2-ylmethylene)ethanamine was used for the synthesis of M(II) complexes, [TEM(M)X2] (M = Co, Cu, Zn; X = Cl; M = Cd, X = Br). Structural characterization of the synthesized complexes revealed distorted tetrahedral geometry around the M(II) center. In vitro investigation of the synthesized ligand and its M(II) complexes showed considerable anti-urease and leishmanicidal potential. The synthesized complexes also exhibited a significant inhibitory effect on urease, with IC50 values in the range of 3.50-8.05 μM. In addition, the docking results were consistent with the experimental results. A preliminary study of human colorectal cancer (HCT), hepatic cancer (HepG2), and breast cancer (MCF-7) cell lines showed marked anticancer activities of these complexes.

Thiophene-Derived Schiff Base Complexes: Synthesis, Characterization, Antimicrobial Properties, and Molecular Docking

Novel thiophene-derived Schiff base ligand DE, where DE is (E)-N¹,N¹-diethyl-N²-(thiophen-2-ylmethylene)ethane-1,2-diamine, and the corresponding M(II) complexes, [M(DE)X₂] (M = Cu or Zn, X = Cl; M = Cd, X = Br), were prepared and structurally characterized. X-ray diffraction studies revealed that the geometry around the center of the M(II) complexes, [Zn(DE)Cl₂] and [Cd(DE)Br₂], could be best described as a distorted tetrahedral. In vitro antimicrobial screening of DE and its corresponding M(II) complexes, [M(DE)X₂], was performed. The complexes were more potent and showed higher activities against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, fungi Candida albicans, and protozoa Leishmania major compared to the ligand. Among the studied complexes, [Cd(DE)Br₂] exhibited the most promising antimicrobial activity against all the tested microbes compared to its analogs. These results were further supported by molecular docking studies. We believe that these complexes may significantly contribute to the efficient designing of metal-derived agents to treat microbial infections.

Identification, in-vitro anti-plasmodial assessment and docking studies of series of tetrahydrobenzothieno[2,3-d]pyrimidine-acetamide molecular hybrids as potential antimalarial agents

Malaria is the most lethal parasitic infections in the world. To address the emergence of drug resistance to current antimalarials, here we report the design and synthesis of new series of tetrahydrobenzothieno[2,3-d]pyrimidine-acetamide hybrids by using multicomponent Petasis reaction as the key step and evaluated in vitro for their antimalarial effectiveness. The structure of all the compounds were confirmed by NMR Spectroscopy and mass spectrometry. Most of the compounds showed potent antimalarial activity against both CQ-sensitive (3D7) and CQ-resistant (W2) strains. A8, A5, and A4 are the most potent compounds that showed excellent anti-plasmodial activity against CQ-resistant strain in the nanomolar range with IC₅₀ values 55.7 nM, 60.8 nM, and 68.0 nM respectively. To assess the parasite selectivity, the in vitro cytotoxicity of selected compounds (A3-A6, A8) was tested against HPL1D cells, demonstrating low cytotoxicity with high selectivity indices. Furthermore, these compounds were also evaluated on two additional human cancerous cell lines (A549 and MDA-MB-231), confirming their anticancer effectiveness. The in vitro hemolysis assay also showed the non-toxicity of these compounds on normal uninfected human RBCs. The interaction of these hybrids was also investigated by the molecular docking studies in the binding site of wild type Pf-DHFR-TS and quadruple mutant Pf-DHFR-TS. The in silico ADMET profiling also revealed promising physicochemical and pharmacokinetic parameters for the most active hybrids, which provide strong vision for further development of potential antimalarials.

Crystal structures and hydrogen-bonding analysis of a series of benzamide complexes of zinc(II) chloride

Ionic co-crystals are co-crystals between organic mol-ecules and inorganic salt coformers. Co-crystals of pharmaceuticals are of inter-est to help control polymorph formation and potentially improve stability and other physical properties. We describe the preparation, crystal structures, and hydrogen bonding of five different 2:1 benzamide or tolu-amide/zinc(II) chloride co-crystal salts, namely, bis-(benzamide-κO)di-chlorido-zinc(II), [ZnCl2(C7H7NO)2], di-chlor-ido-bis-(2-methyl-benzamide-κO)zinc(II), [ZnCl2(C8H9NO)2], di-chlorido-bis-(3-methyl-benzamide-κO)zinc(II), [ZnCl2(C8H9NO)2], di-chlorido-bis-(4-methyl-benzamide-κO)zinc(II), [ZnCl2(C8H9NO)2], and di-chlorido-bis-(4-hy-droxy-benzamide-κO)zinc(II), [ZnCl2(C7H7NO2)2]. All of the complexes contain hydrogen bonds between the amide N-H group and the amide carbonyl oxygen atoms or the chlorine atoms, forming extended networks.

Hydrogen-bonded networks in oxygen-coordinated monoamide complexes of zinc(II)

The preparation of the bulky secondary amide N-(2,6-diisopropylphenyl)-2,2-dimethylpropanamide and the determination of its crystal structure at 173(2) K are reported. The structure displays disorder of the tBu methyl groups due to thermal motion and an infinite N–H····O=C hydrogen-bonded chain described by a [Formula: see text] graph set. Reaction of this amide with ZnCl2 or ZnBr2 in tetrahydrofuran (THF) results in dihalo-(tetrahydrofurano)-(N-(2,6-diisopropylphenyl)–2,2-dimethylpropanamido)-zinc(II) complexes (Cl, Br) for which the crystal structures have also been determined. These complexes, as well as a chloroform solvate of the dichloro-complex, contain N–H····X–Zn hydrogen-bonded chains described by [Formula: see text] graph sets. Evaporative crystallization results in the loss of both chloroform and THF to afford crystals determined to be bis(μ2-chloro)-dichloro-bis(N-(2,6-diisopropylphenyl)-2,2-dimethylpropanamido)-dizinc(II) by single crystal X-ray diffraction. This dimeric complex shows a complex network of N–H····Cl–Zn hydrogen bonds describable by [Formula: see text], [Formula: see text], and [Formula: see text] chains, small [Formula: see text] molecular “squares”, and larger [Formula: see text] rings.