Yazar "Khan, Islam Ullah" seçeneğine göre listele

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    Crystallographic Studies of Dehydration Phenomenon in Methyl 3-hydroxy-2-methyl-1,1,4-trioxo-1,2,3,4-tetrahydro-1λ 6-benzo[e][1,2]thiazine-3-carboxylate
    (Springer/Plenum Publishers, 2013) Arshad, Muhammad Nadeem; Sahin, Onur; Zia-ur-Rehman, Muhammad; Shafiq, Muhammad; Khan, Islam Ullah; Asiri, Abdullah M.; Khan, Sher Bahadar
    Methyl 3-hydroxy-2-methyl-1,1,4-trioxo-1,2,3,4-tetrahydro-1 lambda(6)-benzo[e][1,2]thiazine-3-carboxylate was synthesized in single step through in situ bromination of methyl 2-methyl-1,1,4-trioxo-1,2,3,4-tetrahydro-1 lambda(6)-benzo[e][1,2]thiazine-3-carboxylate using dibenzoyl peroxide & N-bromosuccinamide and was crystallized in acetone-ethyl acetate mixture (1:1). However, crystallization in methanol converted the title compound to methyl 3-methoxy-2-methyl-1,1,4-trioxo-1,2,3,4-tetrahydro-1 lambda(6)-benzo[e][1,2]thiazine-3-carboxylate, an unsymmetrical ether. The titled compound C11H11NO6S (3) crystallized in nonoclinic space group P2(1)/c whereas, the compound C12H13NO6S (4) crystallized in triclinic space group P-1. X-ray studies shows that the molecules of 1 are linked into a one-dimensional framework structure by C-H center dot center dot center dot O and O-H center dot center dot center dot O hydrogen bonds, while in 4, intermolecular C-H center dot center dot center dot O and C-H center dot center dot center dot pi hydrogen bonds and a pi center dot center dot center dot pi interaction result in the formation of infinite chains running along the [010] and [001] directions.
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    Efficient Syntheses, Crystal Structure and Thermal Properties of Gabapentin 4-Acetamido, 2-Mesitylene and 2,4-Dinitro Sulfonamides Derivatives
    (Springer/Plenum Publishers, 2019) Kanwal, Nosheen; Khan, Islam Ullah; Sharif, Shahzad; Hussain, Erum Akbar; Mehmood, Arshad; Sahin, Onur
    Efficient syntheses of four derivatives G2-G5 of Gabapentin (G1) have been achieved. The structures of targeted compounds were investigated by elemental analysis, FT-IR, and H-1-NMR spectroscopic method. Crystal structures of G2 and G4 determined by single crystal X-ray diffraction method are also described. In G2 the molecules are stacked over each other in the form of layers and adjacent layers run parallel to each other. Intermolecular hydrogen bonding and van der Waals interactions are responsible for building the molecular assembly and packing of molecules in the unit. In G4, the molecules are arranged in parallel sheets formed by inter-molecular hydrogen bonds. The proposed synthetic route has high impact due to its simple reaction conditions of room temperature, water as a green solvent and short time to accomplish the reaction.
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    Efficient syntheses, crystal structure, thermal and biological evaluation of amlodipine 4-chlorobenzoyl, 4-chlorobenzene and 2,5-dichlorobenzene sulfonamide derivatives
    (Elsevier France-Editions Scientifiques Medicales Elsevier, 2016) Kanwal, Nosheen; Khan, Islam Ullah; Hussain, Erum Akbar; Farid, Sidra; Sahin, Onur
    An efficient synthesis of new A-2, A-3, and A-4 analogues from amlodipine (A-1) has been achieved. All synthesized compounds were investigated by elemental analysis, FTIR, EIMS, and H-1 NMR techniques. Crystal structures of A-2 and A-3 were determined by single crystal X-ray diffraction method. Compound A-2 crystallizes in a monoclinic space group C2/c having unit cell parameters alpha = 23.8754(9) angstrom, b = 8.6725(3) angstrom, c = 30.5777(12) angstrom, beta = 90.673(2)degrees, and V = 6331.0(4) angstrom(3), whereas A-3 crystallizes in a triclinic space group P (1) over bar having unit cell parameters a = 8.2968(3) angstrom, b = 9.3112(4) angstrom, c = 18.1359(7) angstrom, alpha = 100.692(2)degrees, beta = 98.316(3)degrees, gamma = 102.747(2)degrees, and V = 1317.39(9) angstrom(3). These compounds showed that C-H center dot center dot center dot 0 and N-H center dot center dot center dot O hydrogen bonds stabilize the crystal packing. The results of thermal analysis of all products were consistent with the proposed stoichiometry and compounds were found thermally stable up to 200 degrees C. The compounds were tested for direct free radical scavenging effect toward alpha, alpha-Dipheny1-1-picryl hydrazide (DPPH center dot) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS center dot+) radical cation in aqueous phosphate-buffered saline of pH 7.4 and showed significant in vitro antioxidant potential. Antiurease activity was also performed; A-2 and A-4 showed excellent results with dose independency. (C) 2016 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.
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    Facile Synthesis and Crystal Structures of New Ammonium Sulfonates (CA-DNBS and TEA-TMBS)
    (Chinese Journal Structural Chemistry, 2013) Khan, Islam Ullah; Arshad, Muhammad Nadeem; Sahin, Onur; Mubashar-Ur-Rehman, Hafiz; Munir, Ayesha; Humayun, Saba; Asiri, Abdullah M.
    The title compounds, C12H10N3O7SCl (I) and C15H27NO3S (II), crystallize in the monoclinic system, space group P2(1)/c with a = 7.3995(1), b = 27.8489(6), c = 9.8246(2) angstrom, beta = 131.349(1)degrees, V = 1519.82(5) angstrom(3), Z = 4, F(000) = 768, R-int = 0.033 and S = 1.03 for I, and in the orthorhombic system, space group Pbca with a = 8.6227(1), b = 16.1480(4), c = 23.8774(6) angstrom, V = 3324.67(12) angstrom(3), Z = 8, F(000) = 1312, R-int = 0.024 and S = 1.04 for II. We have devised a convenient procedure for the synthesis of fused organic salts resulting from 1:1 proton-transfer, using an amine and a derivative of benzenesulfonic acid. The synthesized salts have a number of applications ranging from their consumption as eco-friendly solvents and catalysts in organic syntheses, to being used as efficient precursors for the production of sulfa drugs. Structures of compounds 3-chloroanilinium 2,4-dinitrobenzenesulfonate (CA-DNBS) and triethylaminium 2,4,6-trimethylbenzenesulfonate (TEA-TMBS) were determined by single-crystal X-ray diffraction studies and infrared spectroscopy.
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    Green and Facile Reaction of Gabapentin with Sulfonyl Chlorides to Synthesize Lactams and Sulfonamides Derivatives in Aqueous Medium
    (Bentham Science Publ Ltd, 2018) Hussain, Erum Akbar; Kanwal, Nosheen; Khan, Islam Ullah; Mutahir, Sadaf; Khan, Muhammad Asim; Ahmed, Maqsood; Mahmood, Arshad
    In the current research, a facile and green one pot synthesis of new gabapentin-lactams (G(2)-G(8)) has been achieved by reacting gabapentin (G(1)) with a variety of sulfonyl chlorides. The new lactamization protocol is furnished under the green solvent i.e., water and reaction was completed in a short period of time by just stirring at room temperature. Whereas in some cases, annulation could not happen and furnished un-cyclized sulfonamide products (G(9)-G(12)). The structures of the targeted compounds were established by elemental analysis, FT-IR, H-1-NMR and mass spectrometry. The crystals of some new lactams (G(2), G(3), G(4), and G(8)) were also evaluated by single crystal X-ray diffraction.
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    Hydrothermal synthesis, structural investigation, and magnetic properties of 2-D layered lanthanide (Ln = Pr, Eu, Gd, Tb, and Er) coordination polymers possessing infinite 1-D nanosized cavities
    (Taylor & Francis Ltd, 2015) Sharif, Shahzad; Sahin, Onur; Khan, Bushra; Khan, Islam Ullah
    Five 2-D Ln(III) coordination polymers, [Ln(PDA)(PDAH)](n) (PDA=2,6-pyridinedicarboxylate), have been obtained under mild hydrothermal condition. In each coordination polymer, PDA is tetradentate and pentadentate, while lanthanides have coordination number eight to generate trigonal prismatic, triangular face bicapped LnO(6)N(2) geometry having 9 triangular and 2 square faces. Two different types of bridging oxygens are responsible to grow the 2-D coordination polymers providing open channels possessing infinite 1-D nanosized cavities. Adjacent 2-D chains are further extended to a 3-D hydrogen-bonded layered network through intermolecular - interactions and C-HO hydrogen bonds. Four lanthanides are arranged roughly at the vertices of a square and bridged by eight carboxylates leading to the overall tetrahedral shape of the secondary building units. The abnormal behavior of lanthanide contraction for the atomic radii of europium can be attributed to overlapping of electron clouds. The overall magnetic behavior is typical for the presence of antiferromagnetic exchange coupling interactions. Thermal decomposition analysis reveals that the coordination polymers have significant thermal stability. The coordination polymers are further characterized using elemental analysis and FT-IR spectroscopy.
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    Seven-, eight-, and ten-coordinated cerium(III) with highly connective pyridine-2,4,6-tricarboxylate, oxalate, and glycine ligands
    (Taylor & Francis Ltd, 2013) Khan, Islam Ullah; Sharif, Shahzad; Sahin, Onur
    Two new 3-D Ce(III) coordination polymers, [Ce-1.3(PTA)(2)(Oxa)(2)(Gly)(H2O)(2)]center dot(Gly)4H(2)O (1) and [Ce-2.6(PTA)(4)(Oxa)(2)(H2O)(10)]center dot(MeOH)7H(2)O (2) (PTA=2,4,6-pyridinetricarboxylate, oxa=oxalate and Gly=glycine), were synthesized. The oxalate in 1 and 2, generated in situ from the cleavage and chemical rearrangement of PTAH(3), assembled into mixed-ligand networks to generate 3-D frameworks. Single crystal analysis reveals that in both complexes, Ce(III) shows coordination numbers of 7 and 10 in 1 and 8 and 10 in 2. PTA adopts four kinds of coordination modes. These complexes were further characterized using elemental analysis, FTIR spectroscopy and thermogravimetric analysis.
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    Synthesis, crystal structure and magnetic properties of an octanuclear cerium(III) complex of pyridine-2,6-dicarboxylate
    (Walter De Gruyter Gmbh, 2019) Sharif, Shahzad; Khan, Islam Ullah; Sahin, Onur; Jabeen, Nadia; Ahmad, Saeed; Khan, Bushra
    An octanuclear compound of cerium(III), [Ce-8(Pydc)(10)(HPydc)(4)center dot 22H(2)O]center dot 11H(2)O (1) (Pydc = pyridine-2,6-dicarboxylate anion) was prepared under mild solvothermal conditions and its crystal structure was determined by single-crystal X-ray diffraction. Three kinds of coordination environments are observed, which include: [Ce(Pydc)(3)], [Ce(Pydc)(H2O)(4)(O,O)], and [Ce(H2O)(7) (O,O)]. Each cerium atom in 1 is nine-coordinated but two different geometries are found. The Ce1 and Ce2 atoms exhibit a nearly tricapped trigonal prismatic CeN3O8 geometry, while Ce3 and Ce4 possess CeNO8 and CeO9 coordination polyhedra, which approximate to slightly distorted mono-capped square antiprisms having 12 triangular faces. The Pydc ligands adopt tri-, tetra-, and penta-coordination modes through tridentate chelating and, mu(2) and mu(3)-bridging modes, respectively. The clusters are joined by O-II center dot center dot center dot O hydrogen bonds to generate 3D supramolecular network. Magnetic susceptibility measurements for 1 indicate that the chi(m) values obey the Curie-Weiss law. The overall magnetic behavior is typical for the presence of antiferromagnetic exchange coupling interactions between the cerium(III) ions.