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  • Open access
  • 54 Reads
Synthesis of novel bisiminophosphorane palladacycles with miscellaneous bidentate chelating ligands

Bisiminophosphorane palladacycles were synthesized efficiently through the cyclometallation process providing tetranuclear palladium species with macrocycle-type structures. These ensuing compounds were reacted with different bidentate ligands in a 1:4 ratio. The results showed that only bimetallic complexes with two chelating ligands were obtained. This puts forward that the chelate effect predominates in this process over the macrocycle effect.

  • Open access
  • 88 Reads
Preparation and crystal structure of metallated 2,4,6-trimethylaniline imines

In a typical condensation reaction, Schiff Base ligands were synthetized from 2,4,6-trimethylaniline and the appropriate aldehydes. Treatment of the ligands with the corresponding palladium salt provided dinuclear cyclometallated compounds with bridging acetate moieties. The X-ray crystal structure analysis carried out was in agreement with the spectroscopic data. Herein we describe the preparation of the complexes; a brief discussion of the crystal structure is also given. The resulting dinuclear palladacycles are suitable for further ligand-exchange processes.

  • Open access
  • 68 Reads

The alkyne hydrothiolation (thiol-yne click “TYC” reaction), is a simple approach to produce alkenyl sulfides from thiols and alkynes. In our research group, it has been reported a procedure for the synthesis of catechols with thiol pendant groups, interesting for the fabrication of novel materials. Besides, in the last years, we have been working in the development of methodologies based on the use of supported copper nanocatalysts. On this basis, we report our results about the TYC reaction between alkynes and catechol-thiol derivatives catalysed by CuNPs supported on TiO2 in 1,2-dichloroethane (DCE) at 80 °C.

Activated alkynes bearing an adjacent electron-withdrawing group gave conversions from good to excellent of anti-Markovnikov Z-alkenyl sulfides, while the unactivated alkynes did not react. To explain this, we calculated and compared different methods for deriving partial atomic charges (Mulliken, CHELPG, Hirshfield, NBO) for all the alkynes. Furthermore, since we assumed that the reaction starts when the alkyne is activated by the copper, we modelled the nanocatalyst to find the most simple and representative structure. Computational results allowed us to assume that copper would be attached to a TiO2 dimer through the oxygen atoms. DFT methods with the Gaussian09 and Orca software were used, applying different functionals (M06, M06-L, M06-2X, B3LYP) and basis set (TZVP, 6-311+G*). Moreover, the solvent effect (DCE) was evaluated with the CPCM model.

  • Open access
  • 64 Reads
Synthesis of 2-methyl-3-nitropyridines, 2-styryl-3-nitropyridines and their reactions with S-nucleophiles

Nitroarenes and nitrohetarenes are valuable synthetic intermediates in organic synthesis due to variety of possible chemical transformations. One of the most important and flexible tools for nitroarenes functionalization is nucleophilic aromatic substitution (SNAr). This reaction generally requires number of conjugated electron-withdrawing groups and SNAr of non-activated nitro groups is rather uncommon. Most of these examples were obtained on polynitrobenzenes, but little is known about reactions of non-activated 3-nitropyridines.

Here we report synthesis of several 2-methyl-3-nitropyridines and their reactions with various aromatic aldehydes, leading to corresponding 2-styrylpyridines under mild conditions. Both 2-methyl- and 2-styryl-3-nitropyridines readily react with thiolate-anions and give substitution products in good yields. Chemo- and regioselectivity is discussed, some of 2-styrylpyridines also showed remarkable fluorescent properties.

  • Open access
  • 93 Reads
Microwave assisted facile synthesis and anticancer evaluation of novel ethyl 4-(substituted phenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate

Herewith, we report the design and synthesis of a novel series of ethyl 4-(substituted phenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate derivatives, obtained by condensation of substituted aldehydes, ethyl 3-oxobutanoate and urea in ethanol as solvent and Potassium tert-butoxide as a catalyst under microwave irradiation for about 10-12 min (400 W) at 700C to get structural prerequisite indispensable for anticancer activity. The synthesized derivatives were investigated for MTT assay, enzymatic assay and molecular modeling studies. Most of the compounds were found to be potent in anticancer evaluation.

  • Open access
  • 99 Reads
Microwave assisted facile synthesis and anticancer evaluation of new substituted-3-methyl-1- substituted phenyl-1H-pyrazole

Herewith, we report the design and synthesis of a series of the cyclo-condensation of the substituted hydrazine derivatives with the substituted 1,3-dicarbonyl compound is a simple and rapid approach to obtain substituted pyrazoles. This compound was obtained by using zinc oxide as catalyst and water as a solvent under microwave irradiation for about 12-14 min (450 W) at 900C to get structural prerequisite indispensable for anticancer activity. The synthesized derivatives were investigated for MTT assay, enzymatic assay and molecular modeling studies. Most of the compounds were found to be potent in anticancer evaluation.

  • Open access
  • 51 Reads
Investigation of Acridindion derivatives synthesis with versatile morphologies of Bi2O3 nanoparticles

In this study, the Bi2O3 nanoparticles have been successfully synthesized through a facile hydrothermal procedure. The structure of the Bi2O3 nanoparticles was analyzed by Fourier transfer infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The synthesized Bi2O3 nanoparticles have unique properties such as high activity, high purity, and high surface area. Hence, we have reported the Bi2O3 nanoparticles as an efficient, cost-effective and mild catalyst for the synthesis of acridindione derivatives via one-pot four-component reaction. Also, the effect of morphology of Bi2O3 nanostructure was investigated on catalytic performance. Therefore, Bi2O3 nanorod and nanopowder were prepared and applied as a heterogeneous catalyst in the synthesis of acridindiones. The present approach offers several advantages such as excellent yields within short times, green catalyst and ease of recovery.

  • Open access
  • 52 Reads
Electrosynthesis and Characterization of PANI and PANI/ ZnO composites films.

The polyaniline (PANI) and ZnO doped polyaniline composite (PANI/ZnO) films were synthesized by electrochemical polymerization, on transparent ITO glass substrate. The deposition was carried out by cyclic voltammetry for 10th cycle with potential sweep from -200 to 900 mV vs.SCE, in sulfuric acid medium containing aniline monomer precursor and LiClO4 supporting salt at room temperature. The doping effects of ZnO on PANI properties were studied; electrical properties of PANI and PANI/ZnO composite were estimated from Mott-Schottky analysis which demonstrated an n-type conductivity for all films with carrier concentrations in order of 1017and 1019 for PANI and PANI/ZnO composite respectively. The effect of the concentration of ZnO dopant in the electrolyte on the morphology and the composition of the PANI were investigated from scanning electron microscopy coupled Energy Dispersive Spectroscopy analysis (SEM+EDS). UV-VIS was investigated to study the optical characteristics of the films such as transmittance and band gap energy. The characteristics of the films were found to be depended to the concentration of ZnO particles in the electrolyte during electrochemical polymerization. Fourier transform Infrared (FTIR) confirms the links and the interaction between PANI and ZnO dopant.

  • Open access
  • 109 Reads
Synthesis of novel N-acyl hydrazone-oxazole hybrids and docking studies of SARS-CoV-2 main protease

A novel synthetic strategy to obtain acyl hydrazine-oxazole hybrids in three-step reactions in moderate to good yields is reported. The key step reaction consists in a Van Leusen reaction using a bifunctional component of both an aldehyde and a methyl ester functional groups. The target molecules were evaluated via in-silico by molecular docking with the main protease enzyme of SARS-Cov-2, where two acyl hydralazine-oxazoles yielded good predicted free energy values in comparison to the co-crystalized ligand.

  • Open access
  • 91 Reads
Docking studies of derivates of phenylaminopyrimidines (PAP) as SARS-Cov-2 main protease inhibitors

A set of 18 imine-phenylaminopyrimidines (imine-PAP) 10a-r against the main protease of SARS-CoV-2, is presented. In addition, these compounds have been previously reported by our group. The best receptor-ligand interactions were obtained from 10i, 10m and 10o as shown by their predicted free Gibbs energy of -9.83, -9.71 and -9.02 kcal/mol respectively. This is in comparison with the co-crystalized ligand in the main protease ( -7.78 kcal/mol,). These results provide solid foundation in order to test the imine-PAP compounds in in vitro studies in order to explore the possible inhibition of the main protease of SARS-CoV-2.