Synthesis and structure of 13- and 26-membered crown ethers,derivatives of resorcinol

13- and 26-Membered crown ethers have been synthesized based on resorcinol and 1,8-dichloro-3,6-dioxaoctane. The products with substituents in the benzene ring have been prepared by alkylation of 13-membered crown ether. Complexing properties of the macrocycles have been studied with the use of ion-selective membrane electrodes. The structures of 13- and 26-membered crown ethers have been established by X-ray structural analysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2458–2464, December, 1995.The work was supported by Technical University of Gdansk (Project DS No. 946197/003).     

Synthesis and molecular and crystal structure of 1-allyl-4-[2-cyano-2-(indan-1,3-dione-2-ylidene)ethylidene] -1, 4-dihydroquinoline

The reaction of 1-allyl-4-methylquinolinium bromide with 2-dicyanomethyleneindan-1,3-dione in the presence of a two-fold excess of triethylamine affords 1-allyl-4-[2-cyano-2-(indan-1,3-dione-2-ylidene) ethylidene]-1,4-dihydrogtiinoline, a representative of a new class of merocyanines. The structure of this compound has been established by X-ray structural analysis. A substantial intramolecular charge transfer and a hydrogen bond between the vinyl hydrogen atom and the indandione oxygen atom have been found.Dedeased in 1995Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 173–176, January, 1996.     

3-(5-Substituted 2-Methoxyphenyl)-4-Nitro-2-Phenyl-5-Thiophene-2-yl-Isoxazolidines - Synthesis and Conformational Studies

Abstract

The synthesis of a new set of 2,3,4,5-substituted isoxazolidines having a sulfur containing heterocyclic moiety has been described. The structural features of the compounds have been analyzed by ¹H and ¹³C NMR spectroscopy as well as by single crystal X-ray studies.

[Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: .cif file.]     

Inhaltsstoffe des Osmanthus-Absolues 6. Mitteilung. (7S, 10S, 5E)- und (7R, 10S, 5E)-2,6,10-Trimethyl-7,10-epoxy-2,5,11-dodecatrien

Constituents of Osmanthus Absolute, 6th Communication. (7 S , 10 S , 5 E ) - and (7 R , 10 S , 5 E )-2,6,10-Trimethyl-7,10-epoxy-2,5,11-dodecatriene Two novel sesquiterpenoid oxides 1a and 1b from Osmanthus absolute have been identified. Their structural proof is based on pectral data and synthesis starting from the known methyl [5-methyl-5-vinyl-tetrahydrofur-1-yl] ketones ( 4a and 4b , respectively), whose configuration is well established. The thus obtained compounds 1a / 1b identical with the natural products, were accompanied by their corresponding 6-methylidene isomers 3a and 3b which could not be detected in the natural substrate.     

One-Bond 13C, 13C-Spin Coupling in η4-, η3- and η2-Olefin Transition Metal Complexes

One-bond ¹³C, ¹³C-spin-coupling constants have been measured, with natural isotope abundance, in η⁴-diene, η³-allyl and η²-ene transition-metal carbonyl complexes. Typical values of ¹J(C,C) are given for Fe-, Ru- and Os-complexes with the three types of olefinic ligands. The effects of substituents and the structural significance of the C,C-coupling constants are discussed.     

Synthesis,molecular structure,and absolute configuration of 1-α-pheitylethyl-3-(2-cyanoethyl)-4-piperidone

The Michael addition of acrylonitrile to the pyrrolidine enamine of 1-(S--phenyl-ethyl)-4-piperidone proceeds with the formation of. a 1:1 mixture of l-(S--phenyl ethyl)-3-(2-cyanoethyl)-4-piperidone diastereomers. A diastereomer isolated in pure form was shown by x-ray diffraction structural analysis to have S-configuration of the new chiral center at C₍₃₎ of the piperidone ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp, 1656–1662, December, 1985.     

Complete spectroscopic structural characterization of novobiocin,isonovobiocin, decarbamylnovobiocin, 2″-(o-Carbamyl)novobiocin,and novobiocin-2″,3″-carbonate

The rigorous structural characterization of novobiocin, is reported using mass spectrometric, infrared and nmr spectroscopic analysis. Complete nmr assignments are reported. Previous reports in the literature had left some quaternary carbon resonances unassigned. Isonovobiocin and decarbamylnovobiocin, although known in the literature for a number of years, have never been completely characterized. Mass spectrometric fragmentation pathways and complete ¹H and ¹³C nmr assignments are reported for these congeners for the first time. The mass spectral fragmentation pathway and nmr assignments are also reported for 2″-(O-carbamyl)novobiocin although the nmr assignments at lower field were reported previously. The structural characterization of novobiocin-2″,3″-carbonate observed in the Test Assay procedure used for Novobiocin is reported for the first time.     

Synthesis of chiral glycolurils from (<Emphasis Type="Italic">S</Emphasis>)-(+)- and (<Emphasis Type="Italic">R</Emphasis>)-(-)-1-<Emphasis Type="Italic">sec</Emphasis>-butyl-3-methylurea

Chiral dialkyl- and tetraalkylglycolurils have been obtained using chiral (S)-(+)- and (R)-(-)-1-sec-butyl-3-methylurea as starting materials. The diastereomer (S)-(+)-2,6-di-sec-butyl-4,8-dimethyl-2,4,6,8-tetraazabicyclo[3.3.0]-octane-3,7-dione was separated into stereoisomers, for the higher melting of which the absolute configuration was determined as (S,S,S,S) by X-ray structural analysis.     

Viscosity of binary mixtures of 2-ethoxyethanol with ethylene glycol,diethylene glycol,triethylene glycol and tetraethylene glycol systems at T = (293.15, 298.15 and 303.15) K

Viscosities, at T = 293.15, 298.15 and 303.15 K, in the binary mixtures of 2-ethoxyethanol with ethylene glycol, diethylene glycol, triethylene glycol and tetraethylene glycol have been measured as a function of composition. From the experimental data the deviations in the viscosity have been calculated. The viscosity data, at T = 298.15 K, were correlated with equations of Hind et al., Grunberg and Nissan, and Frenkel. The results are discussed in terms of intermolecular interactions and structural properties of studied binary mixtures.     

Structures,stabilities, and energies of isomerization of some alkyl cyanides and isocyanides and their corresponding α-cyanocarbonium and α-isocyanocarbonium ions

Ab initio STO -3G geometry-optimized calculations have been performed on methyl, ethyl, and isopropyl cyanides and isocyanides, and the cations formed on abstraction of an α-hydride ion. Stabilization energies of the cations and cyanide–isocyanide isomerization energies have been calculated and correlated with structural features and population analyses.     

Molecular and crystal structure of <Emphasis Type="Italic">trans</Emphasis> and <Emphasis Type="Italic">cis</Emphasis> isomers of 3-cyano-4-[2-(4-methoxyphenyl)vinyl]-6,6-dimethyl-5,6-dihydro-2H-pyran

Monocrystals of the trans and cis isomers of 3-cyano-4-[2-(4-methoxyphenyl)vinyl]-6,6-dimethyl-5,6-dihydro-2H-pyran have been obtained and an X-ray structural analysis of them has been carried out. Both compounds have a molecular structure corresponding to symmetry group C₁. The heterocyclic ring is in a distorted envelope conformation. The crystals of the trans isomer are rhombic and have a fir-tree type of packing. The crystal packing of the cis isomer is formed by pairs of molecules, each of which consists of only one enantiomer. *Dedicated to deeply respected Professor Hank van der Plas in connection with his jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 535-540, April, 2009.     

Syntheses,structural characterization,and properties of Mn(II) and Cd(II) complexes from 5-[4-(1H-imidazol-1-Yl)phenyl]-1H-tetrazole

Reactions of Mn(II) and Cd(II) salts with 5-(4-(1H-imidazol-1-yl)phenyl)-1H-tetrazole (HL) under hydrothermal conditions result in complexes [Mn(L)₂(H₂O)₄] · 2H₂O (I) and [Cd(L)₂(H₂O)₂] (II), which have been characterized by single crystal and powder X-ray diffractions (CIF files CCDC nos. 943861 (I), 943862 (II)), IR spectroscopy, element and thermogravimetric analyses. Two complexes exhibit structural diversity dependent on different metal salts. Complex I shows discrete mononuclear structure, which can be further linked to build a 3D supramolecular framework through hydrogen bonding interactions. Complex II displays 1D zigzag-chain structure, and an extended 3D framework can be formed by hydrogen bonding. Interestingly, tetranuclear water clusters were generated in I, which can be linked by Mn²⁺ ions to show 1D metal-bridged water cluster-chain structure. The present work provides an example that metal centers impact on coordination modes of ligand and consequent structural variation of resulted complexes. Moreover, fluorescence property of II was investigated.

     

Propellanes. LXVI. Exo- and Endo-Diels-Alder adducts of 4-substituted 1,2,4-triazoline-3, 5-diones with various 1, 6-methano [10]annulenes

Relatively few exo-adducts have been obtained from the title compounds. Only one such mono-adduct, 3 , is known. Several exo-endo-bis-adducts have been obtained but the structure of one of these, 5 , has been proved unequivocally by X-ray structural determination.     

Density, Refractive Index, and Related Properties for 2-Butanone + n-Hexane Binary Mixtures at Various Temperatures

Density refractive index n and the related properties molar volume V and molar refraction R have been investigated for 2-butanone + n-hexane liquid binary mixtures over the entire composition range and a wide range of temperatures. Some well-known relationships have been applied to study the temperature and composition dependence of the measured and derived quantities. Furthermore, the deviations of the respective excess properties V ^E, n ^E, and R ^E have been examined, with the aim of identifying particular intermolecular interaction patterns responsible for the macroscopic behavior of these binary mixtures. The results have been interpreted on the basis of structural and geometric effects between the components.     

Elusive Double Perovskite Iodides: Structural,Optical, and Magnetic Properties

Halide double perovskites [A₂M^IM^IIIX₆] are an important class of materials that have garnered substantial interest as non-toxic alternatives to conventional lead iodide perovskites for optoelectronic applications. While numerous studies have examined chloride and bromide double perovskites, reports of iodide double perovskites are rare, and their definitive structural characterization has not been reported. Predictive models have aided us here in the synthesis and characterization of five iodide double perovskites of general formula Cs₂NaLnI₆ (Ln=Ce, Nd, Gd, Tb, Dy). The complete crystal structures, structural phase transitions, optical, photoluminescent, and magnetic properties of these compounds are reported.     

New Biphenyl‐Based Bispyrazolines: Synthesis,Antimicrobial, and Docking Studies

In this study, a series of new bispyrazolines 8 ( a – f ) have been prepared from the cyclization reactions of bischalcones 7 ( a – f ) with phenyl hydrazine by refluxing under the alkaline alcoholic (KOH/EtOH) conditions. The O‐alkylation reactions of hydroxyl substituted chalcone 6 with different 1,ω‐dibromoalkanes in the presence of anhydrous potassium carbonate, tetrabutylammonium iodide, and dry acetone afforded the symmetrical new bischalcones 7 ( a – f ) in good yields. Chalcone 6 was realized by using the Claisen–Schmidt reaction of m‐hydroxyacetophenone with bipheny‐4‐carboxaldehyde. The various spectroscopic parameters such as IR, ¹H‐NMR, ¹³C‐NMR, and ESI‐MS have been thoroughly used for the structural interpretations of the newly prepared products. The in vitro antibacterial and antifungal activities of these compounds have been examined with the help of serial tube dilution method, and many of the tested products were found to be revealing the promising antimicrobial properties, which were evident from their minimum inhibitory concentration values. The molecular docking simulations of the synthesized substances have also been achieved to observe the structural association into the active site of the Escherichia coli FabH (PdB: 3IL9). Docking results of these compounds suggested that bispyrazoline 8b demonstrated the lowest binding energy that describes its higher stability into the pocket of E. coli. The excellent inhibitory activity of this bisheterocycle against E. coli FabH may be ascribed on the basis of hydrophobic and van der Waals interactions.     

Synthetic,spectroscopic, thermal,and structural studies of antimony(III) bis(pyrrolidinedithiocarbamato)alkyldithiocarbonates

An account of the synthesis, spectroscopic, thermal and structural behavior of antimony(III) bis(pyrrolidinedithiocarbamato)alkyldithiocarbonates is presented. The reaction of antimony(III) bis(pyrrolidinedithiocarbamate) chloride with potassium organodithiocarbonate in equimolar ratio yielded the corresponding mixed derivatives of the type [(CH₂)₄NCS₂]₂SbS₂COR [where R = Me, Et, Pr ⁿ , Pr ⁱ , Bu ⁿ , and Bu ⁱ ]. These newly synthesized complexes have been characterized by physicochemical [molecular weight determination, melting points, and elemental analysis], spectral [UV, IR, far-IR, NMR (¹H and ¹³C)], thermal [TG, DTA, and FAB⁺ mass], and structural [powder XRD and SEM] studies. Analytical studies leads to purity and structural properties of the synthesized complexes on the other hand powder X-ray diffraction and SEM studies show that multiphase, polycrystalline, and rod-shaped complexes have been formed having nanorange crystallite size and monoclinic crystal system.     

Density and temperature effect on hydrogen-bonded clusters in water - MD simulation study

Molecular dynamics NVE simulations have been performed for five thermodynamic states of water including ambient, sub-and supercritical conditions. Clustering of molecules via hydrogen bonding interaction has been studied with respect to the increasing temperature and decreasing density to examine the relationship between the extent of hydrogen bonding and macroscopic properties. Calculations confirmed decrease of the average number of H-bonds per molecule and of cluster-size with increasing temperature and decreasing density. In the sub-and supercritical region studied, linear correlations between several physical quantities (density, viscosity, static dielectric constant) and the total engagement of molecules in clusters of size k > 4, P _k>4, have been found. In that region there was a linear relationship between P _k>4 and the average number of H-bonds per water molecule. The structural heterogeneity resulting from hydrogen bonding interactions in low-density supercritical water has been also discussed.      

Synthesis,properties, and X-ray crystal structures of two Ag(I) complexes with 2-(pyridin-4-yl)-1H-imidazole-4,5-dicarboxylic acid

Two 1-D and 3-D Ag(I) complexes involving 2-(pyridin-4-yl)-1H-imidazole-4,5-dicarboxylic acid (H₃PIDC) have been characterized by infrared spectrum, elemental analysis, and single-crystal X-ray diffraction. [Ag₂(HPIDC)]_n (1), synthesized under hydrothermal conditions, gave a 3-D framework; [Ag₂(HPIDC)(MBI)]_n (2) (MBI?=?2-methyl-1H-benzo[d]imidazole), with MBI as the second ligand, gave a 1-D zigzag chain and further formed a 3-D supramolecular structure through π···π interactions. The most interesting structural features of these complexes are the presence of C–H···Ag hydrogen bonding interactions and Ag···C weak interactions between the Ag centers and H₃PIDC. Luminescence indicates that 2 has significantly stronger fluorescent emissions than 1 in the solid state at room temperature.