Crystal Forms of the Antiepileptic Lamotrigine: Molecular Salts and Solvates with Fluorobenzoic Acid,Nicotinic Acid, 2-Thiobarbituric Acid, 3-Picoline and Butyl Alcohol

Abstract  

The crystal structures of three salts and two solvated multicomponent crystals of lamotrigine with 4-fluorobenzoic acid, nicotinic acid, 2-thiobarbituric acid, 3-picoline and butyl alcohol are reported. Compound 1a crystallizes in monoclinc system, space group P2₁ with a = 13.3860(5) ?, b = 8.3420(3) ?, c = 15.5200(6) ?, β = 93.524(1)°, V = 1729.78(11) ?³, and Z = 2. Compound 1b crystallizes in monoclinic system, space group P2₁/c with a = 10.6625(7) ?, b = 16.2575(11) ?, c = 13.6346(9) ?, β = 100.904(1)°, V = 2320.8(3) ?³, and Z = 4. Compound 1c crystallizes in triclinic system, space group P[`1] \overline{1} , with a = 10.1309(7) ?, b = 12.0260(8) ?, c = 14.0826(10) ?, α = 71.783(1)°, β = 86.451(1)°, γ = 80.902(1)°, V = 1609.10(19) ?<sup>3</sup>, and Z = 1. Compound 1d crystallizes in monoclinic system, space group P2<sub>1</sub>/c with a = 14.9570(10) ?, b = 8.0230(6) ?, c = 13.8162(10) ?, β = 102.884(1)°, V = 1616.2(2) ?<sup>3</sup>, and Z = 4. Compound 1e crystallizes in triclinic system, space group P[`1] \overline{1} , with a = 7.5710(6) ?, b = 8.5721(7) ?, c = 13.5532(11) ?, α = 85.364(1)°, β = 79.632(1) (1)°, γ = 86.188(1)°, V = 861.19(12) ?³, and Z = 2. Characteristic R₂²(8) dimer is observed in all five structures. A complete hydrogen bonded motif analysis is described. Lamotrigine-lamotrigine base pair is observed in all the structures, except in (1b). In (1c), the R₂²(7) dimer is noticed while, in all other structures R₂²(8) dimer exist between the lamotrigine-lamotrigine base pair. In all the six structures, chlorine atoms of the lamotrigine molecules are not involved in any interactions.     

Locally ideal formulations for piecewise linear functions with indicator variables

In this paper, we consider mixed integer linear programming (MIP) formulations for piecewise linear functions (PLFs) that are evaluated when an indicator variable is turned on. We describe modifications to standard MIP formulations for PLFs with desirable theoretical properties and superior computational performance in this context.     

Sequential C-N and C-O bond formation in a single pot: synthesis of 2H-benzo[b][1,4]oxazines from 2,5-dihydroxybenzaldehyde and amino acid precursors

Functionalized β-aryl alanine ester derivatives were found to undergo rapid C-N and C-O bond formation with quinol carbonyl compounds to afford 2H-benzo[b][1,4]oxazines in good to excellent yields. This unprecedented finding reported herein offers a straightforward, highly efficient, and rapid method for the synthesis of 2H-benzo[b][1,4]oxazines.     

Experimental and numerical investigations of the texture evolution in copper wire drawing

Polycrystalline copper wires are drawn in a single and multiple step for the equivalent area reduction (RA) of ∼33% The single step and multiple step drawing process was simulated using a rate independent crystal plasticity with finite strain, which is implemented as a user routine in commercial finite element package ABAQUS. The texture of the copper wires were characterized by X-ray diffraction (XRD) and compared with the texture based finite element (FE) simulation predictions. Initial 〈10 0〉 fiber decreases during the drawing process and is replaced by 〈1 1 1〉 fiber. The 〈1 1 1〉 oriented grains are predominant in a single step drawing compared to a multiple step of the equivalent area reduction. The finite element analysis takes into account active crystallographic slip and orientation effects during the drawing process. Regions at the interface of die–wire exhibited complex textures, which was widely seen in the multiple step drawing pattern.     

Crystal and Molecular Structure Studies of 1′-Benzyl-8-(4-fluorobenzyl)-8-azaspiro[bicyclo-[3.2.1]octane-3,4′-imidazolodine]-2′,5′-dione

Abstract  

The title compound, C₂₃H₂₃FN₃O₂ has been synthesized and the structure was investigated by X-ray diffraction studies. The compound crystallizes in the triclinic crystal class in the space group P[`1]P\overline{1} with cell parameters a = 9.345(2) ?, b = 10.940(3) ?, c = 11.986(4) ?, α = 72.349(6)°, β = 68.106(18)°, γ = 66.867(5)°, Z = 2 and V = 1027.8(5) ?³. The hydantoin ring adopts a planar conformation and is affected by the π conjugation. The pyrrolidine and piperidine rings in the bicyclo octane moiety adopt envelope and chair conformations respectively. The structure exhibits both inter and intramolecular hydrogen bonds of the type N–H···O, C–H···O and C–H···N. One of the oxygen atoms attached to the hydantoin ring simultaneously accepts two hydrogen bonds to form a three centered hydrogen bonding pattern.     

Total Synthesis of Ouabagenin and Ouabain

All done! A full account of the total synthesis of ouabagenin and ouabain has been described. The synthesis was achieved through a polyanionic cyclization strategy. Degradation studies provide an ultimate proof for a key intermediate observed in the synthesis.

     

Bremsstrahlung shielding parameters in polymer concretes

Concretes are used for shielding in nuclear power plants. Beta radiation is emitted during the nuclear reactions. This beta radiation interacts with the concrete and results in secondary radiation such as bremsstrahlung. Shielding parameters of beta-induced bremsstrahlung in concretes are important in the field of radiation protection. We have evaluated the cross section, yield, intensity and dose rate of beta-induced bremsstrahlung by pure beta nuclides of end point energy ranges from 0.4 to 5?MeV in some polymer-based concretes such as sulfur polymer concrete, barium polymer concrete, calcium polymer concrete, fluorine polymer concrete, chlorine polymer concrete and germanium polymer concrete. We have compared the shielding properties among the studied polymer concretes. The efficiency, intensity and dose rate of bremsstrahlung increases with a maximum energy of beta nuclide and modified atomic number of the concrete. From the detailed study, it is clear that the barium polymer concrete is having large bremsstrahlung dose rate and specific bremsstrahlung constant values than the other studied polymer concretes. This means barium polymer concrete is a good absorber of bremsstrahlung radiation than the other studied polymer concretes.     

Synthesis of Hexagonal ZnO-PQ7 Nano Disks Conjugated with Folic Acid to Image MCF – 7 Cancer Cells

Surface modified ZnO nanomaterial is widely used in the field of bioimaging worldwide due to its optical properties, electronic characteristics and biocompatibility. Fluorescent enhanced, Polyquaternium-7(PQ7) capped, ZnO hexagonal nano disks (ZnO-PQ7) were synthesised by simple wet chemical method. The structural and optical properties of ZnO-PQ7 hexagonal nano disks were characterized using XRD, UV-Visible, Fluorescence, HRTEM, EDAX and FTIR studies. The size of synthesised ZnO-PQ7 were around 30-45 nm as confirmed by HRTEM studies. Fluorescence emission intensity increased with increase in PQ7 concentration. ZnO-PQ7 was further conjugated with folic acid (FA) to target human breast cancer cell line (MCF-7) via EDC/NHS coupling chemistry. Conjugation of folic acid with ZnO-PQ7 was confirmed by FTIR studies. The cell viability study using Methyl thiazolyltetrazolium(MTT) assay has demonstrated that the ZnO-PQ7 conjugated FA composites (ZnO-PQ7-FA) exhibit low toxicity towards MCF-7 up to a concentration of 125 μg/mL. Confocal laser scanning microscopic images confirmed the uptake of ZnO-PQ7-FA nanoparticles by MCF-7 cells. This study reveals ZnO-PQ7-FA nano disks as a potential imaging agent for detection of cancer cells. The synthesis route reported in this article is simple and easy to follow for the synthesis of ZnO-PQ7-FA in bulk quantities with high purity.