Mohamed A. Badawy

Synthesis, spectroscopic, thermal and DFT calculations of 2-(3-amino-2-hydrazono-4-oxothiazolidin-5-yl) acetic acid binuclear metal complexes

The binuclear complexes of 2-(3-amino-2-hydrazono-4-oxothiazolidin-5-yl) acetic acid ligand (HL) with Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) ions were prepared and their stoichiometry was determined by elemental analysis. The stereochemistry of the studied series of metal complexes was established by analyzing their infrared, (1)H NMR spectra and the magnetic moment measurements. According to the elemental analysis data, the complexes were found to have the formulae [Fe2L(H2O)8]Cl5 and [M2L(H2O)8]Cl3 (M=Co(II), Ni(II), Cu(II) and Zn(II)). The present analyses demonstrate that all metal ions coordinated to the ligand via O(9), O(11), N(16) and N(18) atoms. Thermal decomposition studies of the ligand-metal complexes have been performed to verify the status of water molecules present in these metal complexes and their general decomposition pattern. Density Functional Theory (DFT) calculations at the B3LYP/6-31G(*) level of theory have been carried out to investigate the equilibrium geometry of the ligand and complexes. Moreover, charge density distribution, extent of distortion from regular geometry, dipole moment and orientation have been performed and discussed.

Synthesis and anticancer activity of some new thiopyrano[2,3-d]thiazoles incorporating pyrazole moiety.

The knöevenagel condensation of 3-phenyl-4-thioxo-2-thiazolidinone (1) with 1-phenyl-3-aryl-1H-pyrazole-4-carbaldehydes 2a-d in refluxing glacial acetic acid or in polyethylene glycol-400 (PEG-400) at room temperature without catalyst, afforded the corresponding 5-hetarylmethylene derivatives 3a-d. [4+2]Cycloaddition reaction of compounds 3 with N-arylmaleimides, acrylonitrile and ethyl acrylate afforded thiopyrano[2,3-d]thiazole derivatives 5a-p. The anticancer activity of some of the newly synthesized compounds was investigated against different human cancer cell lines (MCF7 and HEPG2) and confirmed by molecular docking. Moreover, the structure for one representative example of the new products was confirmed by X-ray crystallography. The structure of all the newly synthesized compounds was established by elemental and spectral data.

Synthesis, spectroscopic, thermal and biological activity studies on triazine metal complexes.

The coordination behaviour of the triazine ligand with NNO donation sites, derived from 3-benzyl-7-hydrazinyl-4H-[1,3,4]thiadiazolo[2,3c][1,2,4]triazin-4-one (HL), towards some metal ions namely Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) are reported. The metal complexes are characterized based on elemental analyses, IR, (1)H NMR, solid reflectance, magnetic moment, molar conductance and thermal analyses (TG, DTG and DTA). The ionization constants of the organic ligand under investigation as well as the stability constants of its metal chelates are calculated spectrophotometrically at 25°C. The chelates are found to have octahedral geometrical structures. The ligand (HL) and its binary chelates are subjected to thermal analyses (TG, DTG and DTA) and the different activation thermodynamic parameters are calculated from their corresponding DTG curves to throw more light on the nature of changes accompanying the thermal decomposition process of these compounds. The synthesized ligand and its metal complexes were found to have biological activity against the desert locust Schistocerca gregaria (Forsk.) (Orthoptera - Acrididae) and its adult longevities.

Synthesis, Spectroscopic, and Thermal Characterization of Thiazole Metal Complexes: Biological Activity Studies

Metal complexes of the organic ligand with N azomethine and N thiazole donation sites, derived from 3-(2-(2-(2,6-dichlorobenzylidene)hydrazinyl)-4-oxo-4,5-dihydrothiazol-5-yl) acetic acid (H2L), with some transition metal ions, namely Mn(II), Fe(III), Co(II), Ni(II), Cu(II), and Zn(II), are reported. They are characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, and molar conductance. The ionization constants are found to be 5.57 and 11.50, which can be attributed to loss of the hydrazo and the carboxylic acid protons, respectively. The stability constants of metal chelates, is calculated spectrophotometrically at 25°C, and the order of stability follows the Irving and Williams order. The chelates are found to have octahedral geometrical structures. The ligand (H2L) and its binary chelates are subjected to thermal analyses, and the different activation thermodynamic parameters are calculated using Coats-Redfern equation. The ligand and its metal complexes show a remarkable biological activity against the desert locust Schistocerca gregaria (Forsk) (Orthoptera – Acrididae) and its adult longevities.

Synthesis of some new 5-substituted-3-phenyl-4-thioxo-2-thiazolidinones and their fused thiopyrano[2,3-d]thiazole derivatives

The new 5-arylmethylene-3-phenyl-4-thioxo-2-thiazolidinone derivatives have been synthesized by condensation of ω-(4-formylphenoxy)acetophenone derivatives with 3-phenyl-4-thioxo-2-thiazolidinone, in good yields. The cycloaddition of the newly synthesized compounds to N-arylmaleimides, ethyl acrylate and ω-nitrostyrene has been studied. Under thermal reaction conditions [4+2] cycloaddition proceeds with complete site- and regioselectivity to yield the new fused thiopyrano[2,3-d]thiazole derivatives. GRAPHICAL ABSTRACT

Green synthesis of some new thiopyrano[2,3-d][1,3]thiazoles using lemon juice and their antibacterial activity

Abstract A simple green method has been developed for the synthesis of a series of new 3-phenyl-6-(substituted)-thiopyrano[2,3-d]thiazole-2,5,7(6H)-triones, 6-cyano-2-oxo-3-phenyl-thiopyrano[2,3-d]thiazoles, 3-phenyl-3,5,5a,11b-tetrahydro-2H,6H-chromeno-[4′,3′:4,5]thiopyrano[2,3-d]thiazole-2,6-dione and 5-amino-6-cyano-2-oxo-3-phenyl-3,7-dihydro-2H-thiopyrano[2,3-d]thiazoles via hetero-Diels–Alder reaction by conventional method and green method using lemon juice as natural acid. The structure of all the newly synthesized compounds was interpreted by elemental analyses and spectral data. The synthesized compounds were evaluated for their in vitro antibacterial activity against some pathogenic bacteria. This study is a platform for the future design of more potent antimicrobial agents. Graphical Abstract