Mei Luo

Coordination complexes play a crucial role in modern research. 4-benzopyranone-2-carboxylic acid is a fascinating class of molecules with numerous applications, including the synthesis of pharmaceuticals and valuable chiral compounds. Antibacterial and tuberculostatic medicines, HIV protease inhibitors, intermediates in organic synthesis, and organic catalysis are only a few of the biological applications of chiral complexes. In this study, the synthesis of four metal complexes, C₃₀H₂₈N₂NiO₁₂ [Ni(bzpyr)₂(py)₂(H₂O)₂] (I), C₃₀H₂₄CoN₂O₁₀ [Co(bzpyr)₂(py)₂(H₂O)₂] (II), C₂₀H₂₀O₁₃Zn [Zn(bzpyr)₂(H₂O)₃] (III), and C₃₀H₂₂CuN₂O₉ [Cu(bzpyr)₂(py)₂(H₂O)] (IV), is reported via direct reactions of 4-benzopyranone-2-carboxylic acid with metal salts and pyridine in anhydrous ethanol. Single-crystal X-ray diffraction analysis revealed that complexes I and II crystallize in the chiral space group P-1, whereas III and IV crystallize in the centrosymmetric space group P2₁/c. The structures of these complexes were further characterized by infrared spectroscopy, UV-Visible Diffuse Reflectance Spectroscopy, electrospray ionization mass spectrometry (ESI-MS), elemental analysis, nuclear magnetic resonance, electron paramagnetic resonance spectroscopy and single-crystal X-ray diffraction. In addition, the cytotoxic activities of complexes I–IV were evaluated against the human tumor cell lines K562, A549, HepG2, MDA-MB-231, and SW480, and molecular docking studies were conducted on the four complexes.

In this experiment, the excellent coordination ability of sulfur-containing ligands was utilized. Diphenylacetyl disulfide and 3,3′-diaminodiphenyl sulfone were selected as ligands, and Cu(NO₃)₂·3H₂O, Ni(NO₃)₂·6H₂O and ZnCl₂ were reacted under one-pot conditions to synthesize three mononuclear complexes: [C₄H₁₈CuO₁₂S₂](I), [C₁₂H₁₈N₄NiO₁₁S](II) and [C₂₄H₂₄Cl₂N₄O₄S₂Zn](III). Complex (I) belongs to the orthorhombic crystal system with space group Pbca, while complexes (II) and (III) belong to the monoclinic crystal system with space groups P21/n and P2/n. The crystal structure of the complex was determined using X-ray diffraction (XRD). The structure of the complex was analyzed using infrared Fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–Vis), nuclear magnetic resonance (NMR), and electrospray mass spectrometry (ESI-MS), and the thermal stability and composition of the complex were detected via thermogravimetry (TGA). In terms of application, the biological activity of complexes (I)–(III) in human cancer cell lines (lung cancer A549, liver cancer SMMC-7721, breast cancer MDA-MB-231, and colon cancer SW480) was tested using the MTS method. The results showed that complex (II) had a good inhibitory effect on breast cancer MDA-MB-231.

Six metal complexes [CuC20H20N6O10] (Ⅰ), [ZnC7H9NO7] (Ⅱ), [CoC21H18N3O15] (Ⅲ), [CoC14H10N2O10] (Ⅳ), [NiC14H10N2O10] (Ⅴ) and [ZnC14H10N2O10] (Ⅵ) have been synthesized under one-pot self-assembly condition with 2,3-pyridinedicarboxylic acid ligand. The structures of the compounds were characterized by elemental analysis (E.A), infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), ultraviolet visible spectroscopy (UV-vis) and single crystal X-ray diffraction analysis. Crystal structure reveal that the coordination number of 2,3-pyridinedicarboxylic acid ligand was 6, and each ligand is connected to a metal ion. The metal is connected to the ligands by n-metal and o-metal bonds, and the structural diversity is controlled by the core metal ions. The IC50 test showed that complex Ⅰ-Ⅵ had low to medium activity on human tumor cell line SMMC-7721, and complex Ⅵ had the best activity, with IC50 value of 21.80.

This review presents a summary of reactions that take place during the “Leuckart-type reaction”. The significance of, as well as recent advancements in, the synthesis of amines through simple and inexpensive methods using readily available raw materials is discussed. This review includes all catalytic and noncatalytic reactions that involve the Leuckart method. Recent studies have shown that at least a quarter of C–N bond-forming reactions in the pharmaceutical industry are occur with the support of reductive amination. Recently, experimental conditions have achieved excellent yields. The “Leuckart-type reaction” is technically associated with Eschweiler–Clarke methylation. Compounds are grouped in accordance with the precept of action. This includes drugs affecting the central nervous system, cardiovascular system and gastrointestinal tract; anticancer drugs, antibiotics, antiviral and antifungal drugs; drugs affecting anxiety; convulsant, biotic, and HIV drugs; and antidiabetic drugs. Therefore, this review supports the development of the Leuckart-type preparation of nitrogenous compounds, as well as their advancement in other areas of human development.

A new type of coordination complexes related with the first transition metal and chiral amino alcohols can effectively fight against the human tumour cell line A549 with an IC₅₀ value of 17.71 μM.

Currently, organometallic complexes involving ligand oxazolines are typically obtained in two sequential steps, where the free ligand is given firstly from a functionalized nitrile by condensation reaction with an amino alcohol in the presence of a Lewis or Bronsted acid catalyst, followed by a further coordination with metal salts to obtain the corresponding oxazolinyl metal complexes. Usually, the yield of the two-step procedure is relatively low; considering that metal oxazoline complexes often contain Lewis acidic metals, it is possible that the two steps may be telescoped. A series of novel chiral organometallic complexes (1–23) were assembled in a single step from nitriles, chiral D/L amino alcohols, and a stoichiometric amount of metal salts (MCl2·nH2O/M(OAc)2·nH2O), with moderate to high yields (20–95%). All the crystalline compounds were fully characterized by NMR, IR, MS, and X-ray analyses.