Studies on pyrrolidinones. Synthesis of 1-[(N-acetylarylamino)methyl]pyroglutamic acid derivatives

Pyroglutamic acid was transformed into 1-[(N-Acetylarylamino)methyl]pyroglutamic acid derivatives by using trimethylsilyl variations of the Mannich reaction.     

Synthesis and characterization of Ni (II), Cu (II), Fe (II) and Fe3O4 nanoparticle complexes with tetraaza macrocyclic Schiff base ligand for antimicrobial activity and cytotoxic activity against cancer and normal cells

This work describes a simple synthesis of complexes of the type [M(C₃₂H₂₈N₄)Cl₂], where M = Ni (II), Cu (II) and Fe (II) and a novel complex of magnetite nanoparticle (Fe₃O₄NP) inside (INS) tetraaza macrocyclic Schiff base ligand (C₃₂H₂₈N₄): [Fe₃O₄NP‐INS‐(C₃₂H₂₈N₄)], which was prepared by using a novel co‐precipitation method of coordinated ferric ion (Fe³⁺) in the complex [Fe(C₃₂H₂₈N₄)Cl₂] under mild conditions. The synthesized compounds were characterized and compared with a various physic‐chemical techniques like: Fourier transform infrared (FT‐IR), ultraviolet–visible spectroscopic techniques (UV–Vis), 1‐dimensional (1D) ¹H‐NMR, ¹³C‐NMR spectroscopic techniques, mass spectra, Powder X‐ray diffraction (PXRD), Vibrating sample magnetometer (VSM), Scanning electron microscopy (SEM), elemental analysis and molar conductance measurements. Furthermore, the highest saturation magnetization was 26.56 emu.g^?1 obtained from [Fe₃O₄NP‐INS‐(C₃₂H₂₈N₄)] (diameter of Fe₃O₄NPs~20.87 nm) that prove easy separation by an external magnetic field. In vitro screening of all the compounds against different species of bacteria and fungi shows that [Fe₃O₄NP‐INS‐(C₃₂H₂₈N₄)] is effective against the tested strains as compared to the tetraaza macrocyclic ligand and selected complexes. The cytotoxic activity of the all compounds was also examined in 3 human tumor cell lines as U87, MDA‐MB‐231 and LS‐174. The complex [Fe₃O₄NP‐INS‐(C₃₂H₂₈N₄)] shows moderate and strong cytotoxic activity against brain cancer, colon cancer and breast cancer (U87, MDA‐MB‐231 and LS‐174 respectively), without showing cytotoxicity towards peripheral blood mononucleocyte (PBMC) cells.     

Bayesian Estimation of the Precision Matrix with Monotone Missing Data

Lithuanian Mathematical Journal - Abstract. This research paper stands for the estimation of the precision matrix of the normal matrix with monotone missing data. We explicitly provide maximum and...     

Synthesis of New 3-Carboxamidine Iminocoumarins and Benzopyrano[2,3-d]pyrimidines

A new approach to synthesis of a series of 3-carboxamidine iminocoumarins derivatives and substituted benzopyrano[2,3-d]pyrimidines was developed. The chemical structure of all the compounds was investigated by infrared, ¹H NMR, ¹³C NMR, mass, and elemental analysis. The anticholinesterase activity of compound 12 was evaluated according to the modified Ellman’s method.     

Convenient Synthesis of a New Series of 3-Triazolonyl Iminocoumarins

3-Cyano-7-diethylamino-N-ethoxycarbonyl-iminocoumarin reacted with different hydrazines as N-nucleophiles to afford, in one step, a new series of 2-N-substituted 3-triazolonyl-iminocoumarins in good yields. In two cases, N-unsubstituted derivatives were also obtained. The structures of all the products obtained were confirmed by infrared, ¹H NMR, ¹³C NMR, and elemental analysis. The optical properties of three of these compounds in dichloromethane and ethanol were reported.     

Application of R.O.P. in polymerization of furanic oligoesters with cyclic esters: Synthesis,characterization and degradation

Furano-Aliphatic copolyesters, such as poly(propylene furanic)-co-(polycaprolactone) (PPF-co-PCL), Poly(propylene furanic)-co-(polylactide) (PPF-co-PLA) and Poly(propylene furanic)-co-(polyglycolide) (PPF-co-PGA) were prepared by ring opening polymerization (R.O.P.) using monomers derived from renewable resources. These copolyesters were characterized by ¹H-NMR, DSC and TGA. The degree of randomness determined by ¹H-NMR is close to 1, reflecting a random distribution, sometimes less than one. This indicates that these polyesters have a character to block. The hydrolytic degradation of polymers was performed at pH 4.35 at 37°C over a period of four weeks. The oxidative degradation proved a mass loss of about 50%.     

Missing boundary data recovering for the Helmholtz problem

This Note is dedicated to the numerical treatment of the ill-posed Cauchy–Helmholtz problem. Resorting to the domain decomposition tools, these missing boundary data are rephrased through an ‘interfacial’ equation. This equation is solved via a preconditioned Richardson algorithm with dynamic relaxation. The efficiency of the proposed method is illustrated by some numerical experiments. To cite this article: R. Ben Fatma et al., C. R. Mecanique 335 (2007).     

A direct approach for continuous topology optimization subject to admissible loading

In the present paper, a method is proposed for topology optimization of continuum structures subject to static and plastic admissibility conditions relative to a prescribed load. A key feature of the method is that, using a finite-element discretization, the form of the resulting topology optimization problem is similar to that of the direct static approach of the limit analysis problem. The proposed method is formulated in plane strain using Tresca materials and is illustrated on example problems taken from the literature.     

Synthesis of New Benzopyrano[2,3-c]pyrazoles and 3-triazolonyliminocoumarins From 3-cyano Iminocoumarin Derivatives

Synthesis of benzopyrano[2,3-c]pyrazoles and 3-triazolonyliminocoumarins was successfully performed using heterocyclization of 3-cyano iminocoumarin or their N-ethoxycarbonylated derivatives with semicarbazide reagents. Elemental analysis, infrared, and ¹H NMR spectral data confirmed the molecular structure of the newly synthesized compounds.