European Journal of Chemistry

Reaction of 4-pyridincarbohydrazide, 2-chlorobenzaldehyde and Cd(II) ion in ethanol resulted the complex trans-[Cd(H₂O)₄(C₁₃H₁₀N₃ClO)₂](NO₃)₂. The title complex was characte-rized by elemental analyses, UV-Vis and IR spectroscopy. The structure of complex also was established by single crystal X-ray diffraction analysis. The [Cd(H₂O)₄(C₁₃H₁₀N₃ClO)₂](NO₃)₂complex has monomeric structure with monoclinic crystal system and space group of P2₁/n, a = 7.7720(16) Å, b = 17.594(4) Å, c = 11.823(2) Å, β = 97.29(3)° with Z = 2. The cadmium atom in the crystal structure has octahedral geometry by coordination of the two nitrogen atoms of ligand and four oxygen atoms of water molecules.

A series of new pyrazolo[3,4-d]pyrimidine compounds were synthesized in excellent yields via sulfuration and 1,3-dipolar cycloaddition and confirmed by MS, FT-IR and NMR techniques. All the prepared compounds were screened in vitro for their α-amylase and α-glucosidase inhibitory activities. Preliminary results indicated that some target compounds exhibited promising α-amylase and α-glucosidase inhibitory activity potency. Among the tested products, the cycloadduct f was found most active inhibitor (IC₅₀ = 134.30 μM) for α-amylase, and the sulphur product b is the most active inhibitor (IC₅₀ = 16.37 μM) for α-glucosidase.

The organo-inorganic polymer, poly[{Cu(NO₂-acac)₂}₃]_n, has been prepared and its crystal structure was determined. The structure consists of a trimeric unit in which, acetylacetone ligated symmetrically to copper atoms that pose in the center of octahedrons. The three octahedral fragments of the trimer are linked to each other through nitro group. Crystal Data: C₁₀H₁₂CuN₂O₈, M_r = 351.76, triclinic, P-1 (No. 2), a = 5.8237(2) Å, b = 7.7963(3) Å, c = 7.8847(3) Å, α = 81.988(2)^°, b = 75.294(2)^°, γ = 72.217(2)^°, V = 328.98(2) Å³, T = 143(2) K, Z = 1, Z' = 0.5, μ(Mo Kα) = 1.703, 3021 reflections measured, 1421 unique (R_int = 0.0156) which were used in all calculations. The final wR₂ was 0.0686 (all data) and R₁ was 0.0217 (I > 2σ (I)).

The Sips model for heterogeneous systems was used to describe the immersion enthalpy, maximum adsorption capacity at three temperatures, namely, 283, 291 and 308 K; and interactions between phenol aqueous solutions and activated carbon modified on its surfaces by impregnation with 6.0 M HNO₃ and 3.0 M H₃PO₄ solutions. Activated carbon properties, such as porosity, Brunauer-Emmett-Teller (BET) surface area and volume and size pore distributions, were determined using N₂ adsorption at 77 K. Surface area values were calculated to be between 469 and 864 m²/g. Also, the pH at the point of zero charge, acidity and total basicity for the activated carbons were obtained. The result showed that the Sips model in addition to describe the phenol concentration in equilibrium can be used to study immersion enthalpy when 1/n_s is equal to 1.

Oximes and nitrate esters are considered as important nitric oxide (NO) donors with diverse biological activities. Herein, we report the synthesis and characterization of new oxime and nitrate ester derivatives of norfloxacin as potential NO donor hybrids with expected synergistic antimicrobial activity. The release of NO from those hybrids was measured by a modified Griess method in which p-nitroaniline was employed instead of sulfanilamide. The increased electrophilicity of the intermediate 4-nitroaniline diazonium salt accelerated the coupling process and shortened the overall assessment time. The improved detection limits and enhanced sensitivity would pave the way for the future application of this method in nitrite determination in biological or non-biological systems.

Newly synthesized compounds containing quinoxaline ring fused with tetrazoles and oxadiazoles show array of pharmacological activities, especially, anti-inflammatory, analgesic and anticonvulsant activities. The ability to serve as surrogates or bioisosteres for carboxylic acids, esters and carboxamides made them important moieties in drug designing. Considering the importance of quinoxalines, tetrazoles and 1,3,4-oxadiazoles to both medicinal and heterocyclic chemistry, the following 2-((5-aryl-1,3,4-oxadiazol-2-yl)methoxy)-3-methyl quinoxaline and 3-methylquinoxalin-2-yl-2-(5-aryl-2H-tetrazol-2-yl)acetate derivatives are synthesized. The structures of the synthesized compounds were confirmed by ¹H NMR, ¹³C NMR and Mass spectral data. All the synthesized derivatives were tested in vitro for their antibacterial activity.

This paper reports the preparation and characterization of granular carbon materials those were prepared using chemical activation of African palm stone with ZnCl₂ and then chemically modified in order to increase the nitrogen content. Functionalization processes with activated carbons, modify their textural and chemical characteristics, this fact was observed using N₂ adsorption at 77 K, Boehm titration, infrared Spectroscopy using immersion calorimeter in liquids with different chemical nature (H₂O, C₆H₆, NaOH and HCl). The results show that the solids obtained have BET surface area and pore volume up to 1200 m²/g and 0.44 cm³/g, respectively. Immersion enthalpies of samples are between -9.87 and 141.9 J/g. The results show that with the process of functionalization employed in this work, increasing in the nitrogen content and the modification of the adsorbents surface is achieved. Finally, we found that with this activation and modification procedure, the activated carbons produced have a CO₂ adsorption capacity until 174 mg CO₂ /g.

Two isotype mononuclear yttrium(III) and erbium(III) complexes, {[Y(HL)(OAc)₂(H₂O)₂]. (H₂O)∙(NO₃)} (1) and {[Er(HL) (OAc)₂(H₂O)₂].(H₂O)∙(NO₃)} (2), where HL is the neutral Schiff base ligand 1-(pyridin-2-yl)-2-(pyridine-2-ylmethylene)hydrazine, and OAc is the acetate anion, have been synthesized and characterized by physicochemical methods and single crystal X-ray determination. Both complexes crystallizes in the triclinic space group Pī with unit cell dimensions for complex of Y(III) a = 7.909 (2) Å, b = 11.718 (4) Å, c = 12.497 (3) Å,    α = 78.907 (3)°, b = 73.840 (3)°, γ = 72.074 (3)°, V = 1051.26 (6) ų, Z = 2, R₁ = 0.051 and    wR₂ = 0.112 and for complex of Er(III)a = 7.913 (1) Å, b = 11.719 (2) Å, c = 12.487 (2) Å,          α = 78.832 (1)°, α = 73.674 (1)°, γ = 72.012 (1)°, V = 1049.64 (3) ų, Z = 2, R₁ = 0.028, and   wR₂ = 0.062. In both complexes, the coordination polyhedra around Ln(III) atoms are best described as a distorted tricapped trigonal prism. Antioxidant activities of the ligand and its Y(III) and Er(III) complexes are studied.

A series of new fluoroquinolones analogs (3a-i) were prepared under conventional and microwave irradiation technique. Ethyl 1-cyclopropyl-6,7-difluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylate (1) on reaction with boric acid and acetic anhydride in the presence of catalytic amount of zinc chloride under reflux, resulted in an unstable borate complex. Which was instantaneously treated with morpholine, piperidine, thiomorpholine, 2,6-dimethylmorpholine, 4,5,6,7-tetrahydrothieno[3,2-c]pyridine hydrochloride, 5,6,7,7a-tetrahydrothieno[3,2-c]pyridin-2(4H)-one hydrochloride, 2,3-dichlorophenylpiperazine hydrochloride, 3-(piperidin-4-yl)benzo[d]isoxazole hydrochloride and 5,6,7,8-tetrahydro-[1,2,4] triazolo[4,3-a]pyrazine, in the presence of triethylamine to yield compounds 3a-i. The same compounds on the other hand synthesized using a microwave irradiation technique in the presence of triethylamine and adsorbed neutral alumina. The structures of the synthesized compounds were established on the basis of spectral and analytical data. The antimicrobial activity of newly synthesized compounds were evaluated against different microorganisms and found the compounds exhibited significant activity.

Synthesis of a series of new substituted benzimidazole derivatives by the condensation of     o-phenylenediamine with urea to give 1,3-dihydro-benzimidazol-2-one which reacted with phosphoryl chloride to give 2-chloro-1H-benzimidazole is reported. The product was then alkylated at the benzimidazole NH with different electrophilic reagents leading to functionalized derivatives. Structures of the newly synthesized products have been deduced on the basis of spectral and analytical data. The synthesized compounds were screened for their antimicrobial activity. This exhibited some promising results towards testing organism in-vitro.

This study reports the preparative methods of two types of palladium(II) complexes. The first method revealed two newly palladium (II) complexes derived from bidentate amine ligands, and the second one describes six newly palladium(II) complexes derived from bidentate Schiff base ligands. All the synthesized complexes have been characterized by elemental analysis, conductivity measurements, UV-Visible, FT-IR and ¹H NMR spectral data. In vitro, all the synthesized complexes have been tested for their growth inhibitory activity against Gram negative bacteria Escherichia coli and Gram positive Staphylococcus aureus as well as determining the minimum inhibitory concentration. In addition, the interactions between compounded complexes and human DNA were also studied.

A Grunwald-Winstein treatment of the specific rates of solvolysis of 4-bromopiperidine gives for aqueous ethanol, methanol, acetone, and dioxane a very good logarithmic correlation against the Y_Br solvent ionizing power values with a slope (m value) of 0.46±0.02, consistent with the operation of a synchronous Grob fragmentation mechanism. When the organic component of the solvent is 2,2,2-trifluoroethanol (TFE), the data points show a negative deviation, consistent with an appreciable deactivating interaction of the acidic TFE component of the solvent with the lone-pair of electrons present on the nitrogen.

Protection effect of ethanol extracts of Tapinanthus dodoneifolius leaf (TD extracts) on corrosion of annealed carbon (FE164531) in 2 M HCl and 3.5% NaCl solution has been investigated by weight loss and electrochemical techniques. Surface morphology and elemental analysis was carried out on the corroded specimens using Scanning Electron Microscope/ Energy Dispersive X-ray Spectroscopy (SEM/EDS) to augment results obtained. The data obtained from weight loss revealed that the corrosion protection potentials of TD extract is temperature-concentration dependent. The effectiveness of protection against the corrosive environment increased with increasing extracts concentration but decreased with increased temperature. Electrochemical polarization data showed TD extracts suppressed both the cathodic and anodic processes on FE164531 specimen surface. Calculated thermodynamic parameters showed that TD extracts adsorption process was spontaneous with likely electrostatic interactions which propose physical adsorption, a phenomenon consistent with unfavorable adsorption with increasing experimental temperature. The elemental analysis data show the presence of TD extracts species on FE164531 surface supporting strong adsorption of the extracts on the metal surface while SEM showed lesser corroded surface in the presence of TD extracts.

Tetrakis-(2,4,6-trimethylpyridine)silver(I) dichromate (T-TMPSDC) was easily synthesized by addition of 2,4,6-trimethylpyridine to an aqueous precipitation of silver dichromate and characterized thoroughly, using spectroscopic and others analytical methods such as FT-IR, ¹H NMR, ¹³C NMR, DTA, SEM-EDS and XRD. When T-TMPSDC was used as an oxidative reagent, it showed selectivity in the oxidation of primary, secondary and benzylic alcohols to their corresponding carbonyl compounds in presence of benzylic carbons and arenes such as tetraline, anthracene and phenanthrene.

Dibenzoazepine represents an important class of heterocycles, exhibiting potent antidepressant and anticonvulsant activities. Beside, various modifications on this nucleus, amide analogs at N-5 position showed potent antidepressant activities. A previously reported method for the synthesis of benzamide analogs of dibenzoazepine use hazardous and toxic solvents. Herein, we report a new, efficient and solvent-free green method for the synthesis of dibenzoazepine benzamides (6-21).

A series of new azetidin-2-ones, on the basis of 3-nitrobenzopyran-2-one were synthesized by cyclo-condensation of various Schiff bases of coumarin with acetyl chloride. 4-(2-Amino-ethylamino)-3-nitro-chromen-2-one (3) is synthesized by condensation of 4-chloro-3-nitrobenzopyran-2-one (2) and ethane-1,2-diamine. The catalytic condensation of compound 3 with benzaldehyde, salicylaldehyde or 3-nitrobenzaldehyde yielded corresponding 4-[4-(benzylidene-amino)-phenylamino]-3-nitrobenzopyran-2-ones, 4a-c. The cyclization reac-tion of compounds 4a-c with acetyl chloride yielded corresponding substituted azetidin-2-ones, 5a-c. The structures of the obtained compounds were established by FT-IR and NMR spectrometric data and their elemental analysis. Prepared compounds 4a-c and 5a-c were screened for their antibacterial activity against S. aureus, E. coli and Klebsiella by disc diffusion method. Compounds 4a-c exhibited moderate antibacterial activity, whereas compounds 5a-c displayed significant activity against these microorganisms. The impact of substitutions in antimicrobial activity was also explored.

Title compound, 1-benzoyl-2,7-dimethoxy-8-(3,5-dimethylbenzoyl)naphthalene, an unsymmetrically substituted aromatic diketone compound having non-coplanarly accumulated aromatic rings structure, has been synthesized and its crystal structure has been determined by X-ray crystallography. The asymmetric unit of title compound contains two independent conformers. For each conformer, the two aroyl groups are non-coplanarly situated against the naphthalene ring plane and oriented in an opposite direction. The 3,5-dimethylbenzoyl group leans more than the non-substituted benzoyl group on the other peri-position of the naphthalene ring. The characteristics in the single molecular crystal structure of this unsymmetrical compound show unique relationship with two symmetrically substituted homologues, namely 1,8-dibenzoyl-2,7-dimethoxynaphthalene and 2,7-dimethoxy-1,8-bis(3,5-dimethylbenzoyl) naphthalene. Dihedral angles between 3,5-dimethylbenzene ring and naphthalene ring of 2,7-dimethoxy-1,8-bis(3,5-dimethylbenzoyl)naphthalene are larger than those between benzene ring and naphthalene ring of 1,8-dibenzoyl-2,7-dimethoxynaphthalene. Dihedral angle between 3,5-dimethylbenzoyl group and naphthalene ring in title compound is close to those of symmetrical homologue having two 3,5-dimethylbenzoyl groups. In the similar manner, dihedral angle between non-substituted benzoyl group and naphthalene ring in title compound is also close to those of symmetrical homologue bearing two non-substituted benzoyl groups. On the other hand, the crystal packing of title compound has rather similar feature with 2,7-dimethoxy-1,8-bis(3,5-dimethylbenzoyl)naphthalene. Two compounds have common crystalline molecular structural motif of head-to-head fashioned intermolecular interaction of 3,5-dimethylbenzoyl moieties. It is interpreted that the interactions between (sp³)C–H and π orbital preferentially govern the molecular packing motif. Molecular structure feature of title compound and the symmetrically 3,5-dimethylbenzoylated homologue strongly manifests that accumulation of weak non-classical hydrogen bonds play a crucial role in determination of the crystal packing rather than sole function of stronger non-classical hydrogen bond and π…π stacking.