Synthesis and structure of large 24-mer and 36-mer oxamate-based macrocycles

2017 ◽  
Vol 72 (7) ◽  
pp. 461-474 ◽  
Author(s):  
Saddam Weheabby ◽  
Mohammad A. Abdulmalic ◽  
Evgeny A. Kataev ◽  
Tatiana A. Shumilova ◽  
Tobias Rüffer
Keyword(s):  
Oxalyl Chloride ◽  
Spectroscopic Studies ◽  
Equimolar Amount ◽  
X Ray Diffraction ◽  
Intermolecular Hydrogen Bonds ◽  
X Ray ◽  
Accessible Volume ◽  
Hydrogen Bond Interactions ◽  
Work Up ◽  
Solid State Structures

AbstractPoly(cyclic) oxamates represent novel and potentially multidentate ligands for coordination chemistry. To obtain them, the treatment of 2-nitroaniline with two equivalents of oxalyl chloride afforded N,N′-bis(2-nitrophenyl)oxalamide (1), and by reduction of 1 with [NH4][CO2H] and Pd/C, N,N′-bis(2-aminophenyl)oxalamide (2, bapoxH6) was synthesized. After the addition of an equimolar amount of oxalyl chloride to a THF solution of 2 and aqueous work-up the 24-membered macrocycle H8L2 was obtained. In analogues experiments, the addition of ethoxalyl and oxalyl chloride to 2 afforded the 36-membered macrocycle H12L3. The addition of Cu(OAc)2·H2O and NaOH to 2 gave rise to the formation of [Cu2(bapoxH4)(OAc)2] (4). The identities of 1, 2 and H8L2 were determined by elemental analysis, IR, NMR spectroscopic studies and by mass spectrometry. The solid state structures of H8L2, H12L3 and 4 have been determined by single-crystal X-ray diffraction studies. Macrocycle H12L3 forms chains through intermolecular hydrogen bonds, while packing of 4 consists of layers held by intermolecular dispersion and hydrogen bond interactions. 24-mer H8L2 forms a cavity with a diameter of about 7.5 Å corresponding to an accessible volume of about 120 Å3 according to the well-established 55% solution and was found to bind bromide and iodide anions selectively.

scholarly journals Synthese und Umsetzungen von 4-Acyl/Carbamoyl-N-aryl-3-chloropyrrol-2,5-dionen: Kristallstruktur eines auf Wasserstoffbrückenbindungen basierenden supramolekularen Bandes [1] / Synthesis and Reactions of 4-Acyl/Carbamoyl-N-aryl-3-chloro-pyrrol-2,5-diones: Crystal Structure of a Supramolecular Ribbon Based on Hydrogen Bonds [ 1]

1996 ◽  
Vol 51 (8) ◽  
pp. 1084-1098 ◽  
Author(s):  
Rolf W. Saalfrank ◽  
Bernd Hörner ◽  
Stephan Reck ◽  
Jochen Nachtrab ◽  
Eva-Maria Peters ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Diffraction Analysis ◽  
Thionyl Chloride ◽  
Oxalyl Chloride ◽  
X Ray Diffraction ◽  
Intermolecular Hydrogen Bonds ◽  
X Ray

Reaction of malondiamides 1 with oxalyl chloride (2) leads to the formation of 2,3-dioxo-2,3- dihydrofuran hydrochlorides 3 and 2,3-dioxo-2,3-dihydro-furanes 4, respectively. The structure of 3a was established by X-ray diffraction. The β-oxo-dibenzylamides 5 react with 2 regiospecifically to give the 2,3-dioxo-2,3-dihydrofuranes 6. Addition of water in 1,4-position to 6a yields hydroxy-enol 7, which forms bimolecular aggregates via intermolecular hydrogen bonds as shown by X-ray analysis. Intramolecular C,N-bisacylation of β-oxoamides 8 and malondiamides 11 with 2 leads to the pyrrol-2,5-diones 9 and 12. Reaction of the enols 9 and 12 with thionyl chloride leads to 3-chloro-pyrrol-2,5-diones 13. 3-Amino-pyrrol-2,5-diones 15 are obtained from 13 and amines 14, while 1, ω-diamines 16 yield the bispyrrol systems 17. X-ray diffraction analysis of 17g reveals a supramolecular ribbon based on intermolecular hydrogen bonds between two different conformeres of 17g and in addition establishes unequivocally the imid-structures of 9 and 12. Intermolecular cyclisation of 13 with amino-tetrazol 18 gives the azido-pyrrolo-pyrimidine-diones 20, which reacts with triphenylphosphane to give phosphinimines 22. The structure of 22a was established by X-ray diffraction.

scholarly journals Rapid four-component synthesis of dihydropyrano[2,3-c]pyrazoles using nano-eggshell/Ti(IV) as a highly compatible natural based catalyst

BMC Chemistry ◽  
2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Arefeh Dehghani Tafti ◽  
Bi Bi Fatemeh Mirjalili ◽  
Abdolhamid Bamoniri ◽  
Naeimeh Salehi
Keyword(s):  
Thermo Gravimetric Analysis ◽  
Reaction Times ◽  
Diffraction Field ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solvent Free Conditions ◽  
High Yields ◽  
Work Up

AbstractNano-eggshell/Ti(IV) as a novel naturally based catalyst was prepared, characterized and applied for the synthesis of dihydropyrano[2,3-c]pyrazole derivatives. The characterization of nano-eggshell/Ti(IV) was performed using Fourier Transform Infrared spectroscopy, X-ray Diffraction, Field Emission Scanning Electron Microscopy, Energy-Dispersive X-ray Spectroscopy, and Thermo Gravimetric Analysis. Dihydropyrano[2,3-c]pyrazoles were synthesized in the presence of nano-eggshell/Ti(IV) via a four component reaction of aldehydes, ethyl acetoacetate, malononitrile and hydrazine hydrate at room temperature under solvent free conditions. The principal affairs of this procedure are mild condition, short reaction times, easy work-up, high yields, reusability of the catalyst and the absence of toxic organic solvents.

Water soluble biguanide salts and their 1,3,5-triazine derivatives as inhibitors of acetylcholinesterase and α-glucosidase

2020 ◽  
Vol 235 (10) ◽  
pp. 465-475
Author(s):  
Ozge Gungor ◽  
Seda Nur Kertmen Kurtar ◽  
Muhammet Kose
Keyword(s):  
Spectroscopic Method ◽  
Substitute Aniline ◽  
Water Soluble ◽  
X Ray Diffraction ◽  
Nucleophilic Reaction ◽  
X Ray ◽  
Triazine Derivatives ◽  
Acidic Conditions ◽  
Approved Drugs ◽  
Solid State Structures

AbstractSeven biguanide derivatives were prepared by the nucleophilic reaction between dicyandiamide and p-substitute aniline derivatives or memantine or adamantine under acidic conditions. The cyclization of the biguanide compounds were also conducted via acetone to give 1,3,5-triazine derivatives. The structures of the synthesized compounds were characterized by analytical methods. The solid state structures of [HL5]Cl, [H2L7]Cl2, [HL1a]Cl and [HL5a]Cl were investigated by X-ray diffraction study. The acetylcholinesterase and α-glucosidase inhibitor properties of the compounds were then evaluated by the spectroscopic method. The compounds were found to show considerable acetylcholinesterase and α-glucosidase inhibitory activities compared to the approved drugs. The cyclization of biguanide derivatives with acetone did not affect inhibition of acetylcholinesterase, yet increased the α-glucosidase inhibition.

scholarly journals Insertion of Phosphenium Ions into a Bicyclo[1.1.0]Tetraphosphabutane Iron Complex

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3920
Author(s):  
Martin Weber ◽  
Gábor Balázs ◽  
Alexander V. Virovets ◽  
Eugenia Peresypkina ◽  
Manfred Scheer
Keyword(s):  
Diffraction Analysis ◽  
Room Temperature ◽  
31P Nmr ◽  
Spectroscopic Studies ◽  
Iron Complex ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Phosphenium Ions

By reacting [{Cp‴Fe(CO)2}2(µ,η1:1-P4)] (1) with in situ generated phosphenium ions [Ph2P][A] ([A]− = [OTf]− = [O3SCF3]−, [PF6]−), a mixture of two main products of the composition [{Cp‴Fe(CO)2}2(µ,η1:1-P5(C6H5)2)][PF6] (2a and 3a) could be identified by extensive 31P NMR spectroscopic studies at 193 K. Compound 3a was also characterized by X-ray diffraction analysis, showing the rarely observed bicyclo[2.1.0]pentaphosphapentane unit. At room temperature, the novel compound [{Cp‴Fe}(µ,η4:1-P5Ph2){Cp‴(CO)2Fe}][PF6] (4) is formed by decarbonylation. Reacting 1 with in situ generated diphenyl arsenium ions gives short-lived intermediates at 193 K which disproportionate at room temperature into tetraphenyldiarsine and [{Cp‴Fe(CO)2}4(µ4,η1:1:1:1-P8)][OTf]2 (5) containing a tetracyclo[3.3.0.02,7.03,6]octaphosphaoctane ligand.

Structural Study of an Unusual Diels-Alder Adduct

1992 ◽  
Vol 45 (12) ◽  
pp. 2089 ◽  
Author(s):  
EL Ghisalberti ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Diffraction Study ◽  
Structural Study ◽  
Spectroscopic Studies ◽  
Diels Alder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Naturally Occurring ◽  
Chemical Evidence ◽  
Alder Adduct

The structure of the compound obtained on heating the naturally occurring clerodane furanoditerpene (1) had been formulated as (2) on the basis of spectroscopic studies. A single-crystal X-ray diffraction study on the dihydro derivative of (2) has confirmed this and provides support for the stereochemistry previously assigned to (1) on the basis of chemical evidence.

Salts of purine alkaloids caffeine and theobromine with 2,6-dihydroxybenzoic acid as coformer: structural, theoretical, thermal and spectroscopic studies

2021 ◽  
Vol 77 (11) ◽  
Author(s):  
Mateusz Gołdyn ◽  
Anna Komasa ◽  
Mateusz Pawlaczyk ◽  
Aneta Lewandowska ◽  
Elżbieta Bartoszak-Adamska
Keyword(s):  
Hydrogen Bonds ◽  
Water Solubility ◽  
Theoretical Calculations ◽  
Spectroscopic Studies ◽  
X Ray Diffraction ◽  
Dihydroxybenzoic Acid ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Purine Alkaloids ◽  
Vis Spectroscopy

The study of various forms of pharmaceutical substances with specific physicochemical properties suitable for putting them on the market is one of the elements of research in the pharmaceutical industry. A large proportion of active pharmaceutical ingredients (APIs) occur in the salt form. The use of an acidic coformer with a given structure and a suitable pK a value towards purine alkaloids containing a basic imidazole N atom can lead to salt formation. In this work, 2,6-dihydroxybenzoic acid (26DHBA) was used for cocrystallization of theobromine (TBR) and caffeine (CAF). Two novel salts, namely, theobrominium 2,6-dihydroxybenzoate, C7H9N4O2 +·C7H5O4 − (I), and caffeinium 2,6-dihydroxybenzoate, C8H11N4O2 +·C7H5O4 − (II), were synthesized. Both salts were obtained independently by slow evaporation from solution, by neat grinding and also by microwave-assisted slurry cocrystallization. Powder X-ray diffraction measurements proved the formation of the new substances. Single-crystal X-ray diffraction studies confirmed proton transfer between the given alkaloid and 26DHBA, and the formation of N—H...O hydrogen bonds in both I and II. Unlike the caffeine cations in II, the theobromine cations in I are paired by noncovalent N—H...O=C interactions and a cyclic array is observed. As expected, the two hydroxy groups in the 26DHBA anion in both salts are involved in two intramolecular O—H...O hydrogen bonds. C—H...O and π–π interactions further stabilize the crystal structures of both compounds. Steady-state UV–Vis spectroscopy showed changes in the water solubility of xanthines after ionizable complex formation. The obtained salts I and II were also characterized by theoretical calculations, Fourier-transform IR spectroscopy (FT–IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and elemental analysis.

Comparative Spectroscopic Studies on Luminescence Performance of Er3+ Doped Tellurite Glass Embedded with Different Nanoparticles (Ag Co and Fe) at 0.55 μm Emission

2021 ◽  
Vol 317 ◽  
pp. 81-86
Author(s):  
Syariffah Nurathirah Syed Yaacob ◽  
Md. Rahim Sahar ◽  
Faizani Mohd Noor ◽  
Nur Liyana Amiar Rodin ◽  
Siti Khadijah Mohd Zain ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Ground State ◽  
Tellurite Glass ◽  
Spectroscopic Studies ◽  
The Other ◽  
X Ray Diffraction ◽  
Melt Quenching ◽  
X Ray ◽  
Doped Glass ◽  
Luminescence Performance

The spectroscopic performance of Er3+ doped glass at 0.55 mm emission contain different nanoparticles NPs have been comparatively evaluated. Glass containing 1.0 mol % of Er3+ doped with different NPs (Ag, Co and Fe ) have been prepared using melt quenching technique. X-ray diffraction analysis reveals the all the prepared samples are amorphous. The UV-Vis absorption spectra of all glasses show several prominent peaks at 525 nm, 660 nm, 801nm, 982 nm and 959 nm due to transition from ground state 4I15/2 to different excited of 2H11/2, 4F9/2, 4I9/2, 4I11/2, and 4I13/2. The emission of Er3+ at 0.55 mm for glass contain Ag NP shows significant enhancement about 3 folds up to 0.6 mol%. On the other hand, the emission of Er3+ at 0.55 mm for glass containing Fe NPs and Co NPs intensely quench probably due to the energy-transfer from Er3+ ion to NPs and magnetic contributions.

The structures of benzimidazole derivatives and their potential as tuberculostatics

2018 ◽  
Vol 74 (12) ◽  
pp. 1684-1691
Author(s):  
Marek L. Główka ◽  
Sylwia Kałużyńska ◽  
Malwina Krause ◽  
Katarzyna Gobis ◽  
Henryk Foks ◽  
...  
Keyword(s):  
Multidrug Resistant ◽  
Benzimidazole Derivatives ◽  
X Ray Diffraction ◽  
Intermolecular Hydrogen Bonds ◽  
X Ray ◽  
Resistant Varieties ◽  
Different Types ◽  
Mdr Tb ◽  
Aromatic Systems ◽  
Better Than

Tuberculosis still remains a very important problem, especially its multidrug resistant varieties (MDR-TB). Among the potential tuberculostatics, there are two benzimidazole derivatives, namely 5,6-dimethyl-2-phenylethylbenzo[d]imidazole (1) and (E)-5,6-dimethyl-2-styryl-1H-benzo[d]imidazole (2) which showed significant tuberculostatic activities, better than those of Pyrazinamide and Isoniazyd. Also, the cytotoxicity of 1 appeared promising. The compounds were studied (with the use of X-ray diffraction) in the form of the hemihydrate of 1, C17H18N2·0.5H2O (1a), the methanol hemisolvate of 2, C17H16N2·0.5CH3OH (2a), and the acid oxalate salt of 2, namely (E)-5,6-dimethyl-2-styryl-1H-benzo[d]imidazolium hydrogen oxalate, C17H17N2 +·C2HO4 − (2b). All three structures reveal a similar extended conformation, despite the flexible linker between the two aromatic systems and the different types of strong intermolecular hydrogen bonds. The molecules of 2a are practically planar due to the double bond in the linker, which enables conjugation along the whole molecule, while the molecules of 1a exhibit the possibility of parallel orientations of their aromatic systems, despite the aliphatic (ethyl) linker.

scholarly journals Syntheses, Solid-state Structures and Catalytic Activity of Zinc Carboxylate Complexes in Lactide Polymerization

2014 ◽  
Vol 69 (11-12) ◽  
pp. 1365-1374 ◽  
Author(s):  
Christoph Scheiper ◽  
Christoph Wölper ◽  
Dieter Bläser ◽  
Joachim Roll ◽  
Stephan Schulz
Keyword(s):  
Ring Opening ◽  
Zinc Complex ◽  
X Ray Diffraction ◽  
Polymerization Catalysts ◽  
Co Catalyst ◽  
Carboxylate Complexes ◽  
X Ray ◽  
Carboxylate Groups ◽  
Solid State Structures ◽  
Lactide Polymerization

Abstract Three dinuclear zinc carboxylate complexes [L1-3Zn(μ,η2-O2CPh)]2 (1, 2, 4) containing either the bidentate N,N′-chelating β-diketiminate ligand RNC(Me)C(H)C(Me)NR (R = 2,6-iPr2-C6H3, L1, complex 1), the tridentate O,N,N-chelating ligand OC(Me)C(H)C(Me)NCH2CH2NMe2 (L2, complex 2) or the bis-N,N′-chelating bis-β-diketiminate ligand RNC(Me)C(H)C(Me)NNC(Me)- C(H)C(Me)NR (R = 2,6-iPr2-C6H3, L3, complex 4) were synthesized and characterized including single-crystal X-ray diffraction. Reaction of the neutral bis-β-diketimine (L3(H)2) with two equivalents of ZnMe2 leads to the expected heteroleptic dinuclear zinc complex L3(ZnMe)2 3 in 93% yield. Further reaction with benzoic acid PhCO2H leads to complex 4. Complex 2 forms a rather strong carboxylate-bridged dimer, whereas the carboxylate groups in complexes 1 and 4 act as asymmetrical bridges between both Zn atoms, pointing to the formation of a weakly bonded dimer. The zinc atoms in 1 and 4 are tetrahedrally coordinated, whereas in 2 the coordination number is increased to five due to the coordination of the pendant donor arm. The ring opening polymerization (ROP) of rac-lactide was investigated with the zinc complexes 1-4 and diazabicycloundec-7-ene (DBU) as a co-catalyst. Complexes 2 and 3 are active polymerization catalysts, which in the presence of DBU converted 200 equiv. of rac-lactide into polylactide within 10 min at ambient temperature. The analysis of the crude polymer showed that the lactide polymerization with catalyst 2 occurs via a slightly modified activated-monomer mechanism.

Two copper(II) coordination polymers constructed by bis(4-(1H-imidazol-1-yl)phenyl)methanone and dicarboxylate ligands

2017 ◽  
Vol 72 (4) ◽  
pp. 257-261 ◽  
Author(s):  
Gao-Feng Wang ◽  
Xiao Zhang ◽  
Shu-Wen Sun ◽  
Hong Sun ◽  
Hui Li ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Single Crystal ◽  
Weak Interactions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Elemental Analyses ◽  
Solvothermal Methods ◽  
Solid State Structures ◽  
Aromatic Carboxylate ◽  
Neutral Metal

AbstractTwo new copper(II) complexes, {[Cu(bipmo)(npa)]}n (1) and {[Cu(bipmo)(pa)]}n (2) (bipmo=bis(4-(1H-imidazol-1-yl)phenyl)methanone), were synthesized by solvothermal methods and structurally characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction. The results from single-crystal X-ray diffraction data indicate that the solid state structures of 1 and 2 consist of neutral metal aromatic carboxylate layers, which are pillared by the weak interactions to generate 3D architectures. The topological structures of 1 and 2 are uninodal nets based on 4-connected nodes with the Schläfli symbol of (65·8).

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