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  • Open access
  • 16 Reads
Experimental and theoretical approach to the corrosion inhibition of mild steel in HCl solution by a newly coumarin

New coumarin namely 2-(3-(7-methylcoumarin)acetamido)benzoic acid (MAB) was successfully synthesized by reaction of ethyl 2-(7-methylcoumarin)acetate with anthranilic acid. The chemical structure of MAB was confirmed by FT-IR, NMR and CHN techniques. The inhibition performance of MAB was investigated using the weight loss method. The results illustrate the strong adsorption of MAB molecules on the mild steel coupon surface and this adsorption follows the Langmuir adsorption isotherm. DFT calculations were performed to show the relationship between the MAP molecular structure and inhibition performance.

  • Open access
  • 26 Reads
Sophisticated synthesis of monosubstituted piperazines – from a batch reaction vessel to a flow (microwave) reactor

We report a novel sophisticated synthetic method for preparation of monosubstituted piperazine derivatives, which can now be easily prepared in a one-pot-one-step way from a free piperazine with no need of introduction of a protecting group bringing further disadvantages in terms of time, costs and reduced yields. Reactions proceeding either at room or higher temperatures in common solvents employ with advantage heterogeneous catalysis by metal ions supported on commercial polymeric resins.

Further, we have picked up a set of piperazine derivatives and studied the possibilities of microwave acceleration of given synthetic reactions. Our investigation proceeded from a simple batch technique to the construction of a flow microwave reactor and resulted in promising findings which are summarized and discussed in our contribution.

  • Open access
  • 13 Reads
Synthesis and characterization of some 5-acetylbarbituric based thiosemicarbazone derivatives.

A new series of 5-acetylbarbituric based thiosemicarbazones has been synthesized from 5-acetylbarbituric acid and unsubstituted/substituted thiosemicarbazides (1-6). The synthesized compounds were well characterized by elemental analyses, FT-IR, 1H, 13C NMR and mass spectroscopic methods. Three dimensional molecular structure of three compounds (1, 2 and 6) was determined by single crystal X-ray crystallography. The compounds were evaluated for their in vitro cytotoxicity against HeLa-229 cancer cell line.

  • Open access
  • 24 Reads
Design, Synthesis and Antimicrobial Evaluation of New Norfloxacin-Naphthoquinone Hybrid Molecules

Although the wide arsenal of drugs available to treat bacterial infections, emerging drug-resistant bacterial pathogens have recently highlighted an urgent need to find new more effective and less toxic therapeutic agents.Fluoroquinolones are antibiotics showing a concentration-dependent bactericidal capacity due to the activity inhibition of DNA-gyrase and Topoisomerase IV, which are enzymes essential for bacterial DNA replication. Among them, norfloxacin is mainly active on Gram-(+) bacteria. Naphthoquinones are secondary metabolites showing different biological activities, including cytotoxic, antibacterial and antifungal effects. In particular, the efficacy of natural and synthetic 1,4-naphthoquinone derivatives is likely due to their oxidizing /reducing capability, through which they destroy cellular targets as nucleic acids. Hybrid molecules are obtained combining structural features of two or more bioactive compounds, in order to obtain new therapeutic agents able, not only to reduce undesirable side effects of the parent drugs, but also to inhibit more biological targets, hopefully with a better therapeutic property than the administration of combined single-target drugs. With the aim to apply this strategy in the study of new potential antimicrobial agents, we have designed four molecules by docking calculation on S.aureus DNA gyrase (pdb code: 5CDQ). These compounds were synthesized by the reaction of norfloxacin with the corresponding quinones, and their activities evaluated against both bacteria and fungi, in comparison with synthetic precursors.

  • Open access
  • 25 Reads
Synthesis, Molecular Docking and Biological Evaluation of Some New Benzotriazines

Methyl 2-(4-oxobenzotriazin-3(4H)-yl) alkanoates4a-c proved to be important intermediates for the preparation of some biologically interesting compounds containing the benzotriazinone ring system. Esters 4a-c were prepared by direct diazotization of methyl anthranilate followed by addition of amino acid esters hydrochloride in a one-pot strategy. An equivocal synthesis of methyl 2-(4-oxobenzotriazin-3(4H)-yl) acetate 4a was achieved by alkylation of benzotriazin-4(3H)one with methyl chloroacetate on the basis of chemoselective reaction of heterocyclic amide with electrophiles. A series of N-alkyl-2-(4-oxobenzotriazin-3(4H)-yl) alkanamides7-8(a-h) and methyl 2-(2-(4-oxobenzotriazin-3(4H)-yl)alkanamido)alkanoates (dipeptides) 9-10(a-d) were prepared via azide coupling from 4a-b. Esters 4a-b were converted into the corresponding hydrazides followed by condensation with aldehydes; 4-methoxybenzaldehyde, 4-dimethylamino benzaldehyde and arabinose to afford the corresponding hydrazone derivatives11-13. All the synthesized compounds were subjected to the molecular docking using MOE 2008-10 software as agonist for; E. coli Fab-H receptor and Vitamin D receptor for antibacterial and anticancer evaluation, respectively. The most pronounced strong binding affinity towards the target E. coli Fab-H receptor were compounds 7a, 11a, 11b,10a,10cand 12b. On the other hand, the most pronounced strong binding affinity towards the target Vitamin D receptor were compounds 3, 9c, 11a and 10d. The in vitro antibacterial activity of highest binding affinity docked compounds were tested against E. coli, Staphylococcus aureus and Salmonella spp. All the tested compounds gave effective positive results against E. coli with inhibitory zone of about 1.1 cm, while were inactive against Staphylococcus aureus and Salmonella spp. The in vitro cytotoxic activity of the highest binding affinity docked compounds were tested against human liver carcinoma cell line (HepG2) cancer cell lines. Many compounds showed potent cytotoxic activity with low IC50 values, especially for 3(6.525µM) and 11a (10.97 µM), while for standard drug doxorubicin (5.8 µM).

  • Open access
  • 10 Reads
Sonochemically synthesized microporous metal-organic framework for rapid and efficient ultrasonic-assisted removal of mercury(II) ions in water

Nowadays, water pollution through heavy metal ions is a great concern in all human communities. In this project, metal-organic frameworks (MOFs), which named by Zn2(oba)2bpy, with H2oba = 4,4-oxybisbenzoic acid and bpy = 4,4-bipyridine linkers, were successfully synthesized. Properties of this MOF were performed using different techniques, such as FT-IR, XRD and SEM analysis. These frameworks have special characteristics like rapid, efficient and selective removal of metal ions from contaminated water. The use of an ultrasonic device plays an important role in shortening the absorption time of mercury(II) ions by increasing the absorbent dispersion in the solution. The adsorption capacity was affected by variables such as pH solution, Hg2+ initial concentration, adsorbent dosage and contact time. For Hg(II) metal ions the sorption capacities of 345 mg g-1 and 315 mg g-1 were obtained effectively by Zn2(oba)2bpy structures. The experimental adsorption data for Zn2(oba)2bpy MOF, is well suited with the pseudo-second-order kinetic model (R2 = 0.9912), and the adsorption isotherms of Hg2+ metal ions are in good agreement with the Langmuir model. This work displays to remove Hg2+ ions from pollutant water under 30 min effectively.

  • Open access
  • 6 Reads
Synthesis of a novel porphyrin-based metal organic framework (Co-Por MOF)

In this study, a novel porphyrin-based metal–organic framework (Co-Por MOF) has been successfully synthesized by a simple one-step solvothermal method. we report a metal organic framework based on covalent interaction of an organic linker, 5,10,15,20-tetrakis(4-carboxyphenyl) porphyrin (TCPP) with cobalt clusters. The properties of this material were analyzed by powder X-ray diffraction (XRD), ultraviolet visible adsorption spectroscopy (UV–Vis), fourier-transform infrared spectroscopy (FTIR), differential reflectance spectroscopy (DRS).

  • Open access
  • 18 Reads
Application of a terephthalate and pyrazine-based MOF in Cr adsorption

Metal-organic frameworks (MOFs) are a group of high-porosity materials that had been studying for enormous applications. Today, with increasing the human population and the growth of technology and industry, the entry of various chemical and microbial contaminants such as toxic substances, heavy metals and hospital wastewater into the ecosystem creates new health problems and important health hazards for human and other creatures.[1]

Several methods have been used to remove heavy metals from water, including ion exchange, membrane filtration, chemical deposition, and adsorption in the past two decades. Due to the effectiveness, economic value, flexibility of design and reversibility, absorption techniques are currently one of the technologies used to remove heavy metals. According to the literature, one of the most important features of a good absorbent is its selectivity. Many factors such as electrostatic interactions, covalent interactions, pore size and shape can affect the absorption selectivity.[2]

In order to achieve the purpose of designing MOFs with the ability to absorb metallic contaminants, a metal-organic framework with the formula of [CoNi(µ3-tp)22-pyz)2[ containing nickel and cobalt ions and two types of ligands including terephthalic acid (H2tp) and pyrazine (pyz) was prepared.

In this paper, the adsorption behavior of the named framework was investigated for removal of heavy metal ions and, according to ICP data, it was shown that the Cr ions, as a serious metallic pollutant have a high uptake.

  • Open access
  • 16 Reads
Antibacterial and molecular studying of thiourea derivative ligand and its Dimethyl tin(IV) complex with the superior of its Copper(II) complex as a hepatocellular antitumor drug

1-benzoyl(1,2,4-triazol-3-yl)thiourea [BTThU] ligand and its [dimethyltin(IV), Pd(II) and Cu(II)] complexes are synthesized. The complexes are formed in molar ratio Cu(BTThU)2, DMT(BTThU)2 and Pd(BTThU)2. The characterization has been done by using different physicochemical methods as elemental analyses, IR, 1HNMR and molar conductance measurements. The stability constants of the formed species that produced from the interaction of [BTThU] with dimethyltin(IV) [DMT], dibutyltin(IV) [DBT] and diphenyltin(IV) [DPT] were determined potentiometrically using the non-linear least-square program MINIQUAD-75 in 50% ethanol–water mixture and 0.1M ionic strength at 25oC. Concentration distribution diagrams for these system were evaluated. The theoretical conformational structure analyses were performed using density functional theory for thiol and thione tautomeric forms of [BTThU] ligand and its complex at B3LYP functional with 6-311G basis set for ligand and LANL2DZ basis set for complex. The theoretical vibrational frequency values of the optimized structures were calculated. The charge distribution within the ligand and its dimethyltin(IV) complex was calculated using Mulliken population analysis of [MPA] and natural population analysis [NPA]. The biological activity of BTThU ligand and its dimethyltin(IV) complex were tested in vitro against some selected species of fungi and bacteria. The hepatocellular antitumor effect of all compounds was investigated.

  • Open access
  • 101 Reads
A BODIPY-based fluorescent sensor for amino acids bearing thiol

Fluorescence is a suitable tool to detect and quantify accurately biomolecules in situ thanks to bioimaging techniques. As a matter of fact, cysteine (Cys), homocysteine (Hcys) and Glutathione (GSH) are essential biological thiols relevant to the growth of cells and tissues in living systems. Alterations in the levels of these specific biological thiols have been linked to a number of diseases, such as liver damage, neutral tube defects, Alzheimer’s, and various types of cardiovascular and renal illnesses. Thus, the detection of these amino acids (AA) is highly important to detect, understand and treat these kind of diseases.

To this aim, we have designed a fluorescent sensor based on the BODIPY dye, featuring unsaturated esters at the a-pirrolic position. Both aromatic arms act as reactive sites for these AA and allow the shift of the emission towards the red-edge, thereby, ensuring deeper penetration into tissues. The photophysical signatures of this compound are very sensitive to the presence of these AA (even at the micromolar scale) in the surrounding environments. Thus, up to three channels are available to monitor and quantify AA; the loss of red emission and, mainly, the remarkable increase of the green and yellow fluorescence. Moreover, this ratiometric sensor behaves also as colorimetric sensor, hence, the sensing of the AA in the biological media can be visualized quickly and easily by ‘‘naked eye’’.

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