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Synthesis and Conformational Studies on [3.3.3]Metacyclophane Oligoketone Derivatives, and Their Metal Ion Recognition  [PDF]
Louis Korbla Doamekpor, Raphael Kwaku Klake, Vincent Kodzo Nartey, Takehiko Yamato, Oti Gyamfi, Dennis Adotey
International Journal of Organic Chemistry (IJOC) , 2015, DOI: 10.4236/ijoc.2015.52014
Abstract: Chemical reactions were used to synthesize 2,11,20-tris(ethanedithia)-9,18,27-trimethoxy-6,15, 24-tri-tert-butyl[3.3.3]metacyclophane 2 and 2,11-bis(ethanedithia)-9,18,27-trimethoxy-6,15,24-tri-tert-butyl[3.3.3]metacyclophane 4 from 6,15,24-tri-tert-butyl-9,18,27-trimethoxy[3.3.3]meta-cyclophane-2,11,20-trione 1 and -2,11-dione 3. The yields of 2 and 4 were 70% and 81% respectively. The conformations of the synthesized compounds 2 and 4 were studied using mainly solution Proton Nuclear Magnetic Resonance (1H NMR) spectroscopic methods. Compounds 2 and 4 were found to have a partial-cone conformation. Detailed variable temperature Proton Nuclear Magnetic Resonance studies further confirmed the partial-cone conformation for the two products, 2, 4. During the variable temperature nuclear magnetic resonance spectroscopic studies, compound 2 was found to have a coalescence temperature of about 0?C. Extraction of silver ions with compound 2 gave an extractability of 82% while the parent compound 1 showed zero (0) silver affinity. A 1:1 mol/mol mixture of compound 2 and silver ions studied by solution 1H NMR revealed a novel “Molecular Roulette” type of motion.
Synthesis and Molecular Structure of 4′,9′,4″,9″-Tetra-tert-butyl-1′,6′,1″,6″-tetramethoxy-2,5-dioxa[3.3]metabiphenylophane  [PDF]
Tetsuji Moriguchi,Tatsuya Egami,Akihiko Tsuge
Journal of Crystallography , 2014, DOI: 10.1155/2014/695701
Abstract: A large calixarene-like metacyclophane, 4′,9′,4″,9″-tetra-tert-butyl-1′,6′,1″,6″-tetramethoxy-2,5-dioxa[3.3]metabiphenylophane, was synthesized by an intermolecular condensation reaction of its corresponding bischloromethyl-biphenyl and bishydroxymethyl-biphenyl precursors. After molecular characterization by 1H NMR spectroscopy and mass spectrometry, the compound generated single crystals by recrystallization from a dichloromethane/hexane mixture, facilitating an exact conformational determination via X-ray diffraction analysis. The crystal was found to belong to the monoclinic space group with cell parameters a = 19.908(2)??, b = 9.7193(11)??, c = 23.350(3)??, β = 109.594(1)°, and ?g/cm3 at 90?K. The compound adopted quite strained 1,2-alternate-like conformations because its biphenyl parts displayed large dihedral angles and rigidity. The crystal did not incorporate any solvent molecule but its molecular cavity and crystal space were effectively filled by the substituents. 1. Introduction Calixarenes are cyclic compounds consisting of aromatic rings and methylene bridge chains. In search for novel supramolecular hosts, numerous efforts have been deployed to decorate the upper or lower rim of calixarenes with various functional groups [1–3]. However, the nature of their cyclic skeleton clearly plays a central role in their remarkable performance as host molecules. Members of the metacyclophane family [4–8], calixarenes, are readily obtained by base-assisted condensation of tert-butylphenol and formaldehyde into methylene-based bridges exclusively. In addition, several calixarene analogues such as []metacyclophanes containing oxygen [9, 10] or nitrogen [11, 12] instead of methylene groups in their bridges have been prepared. Cyclic compounds such as calix[4]arenes and large metacyclophanes present various conformations derived from the orientations of the aromatic parts [13]. In addition, the crystal structures of several cyclophanes have been reported using an alternative synthetic pathway [14] and cesium ion template effect [15–19]. Although large metacyclophanes comprising ether bridges and biphenyl units have been synthesized and their host-guest properties were reported [20, 21], their structures in the crystals were not determined. In this study, we report the synthesis of “oxametabiphenilophanes,” a new class of metacyclophanes that incorporate oxygen atoms in bridges and two biphenyl parts thus giving rigidity to the molecules (Scheme 1). A precursor mixture of bischloromethyl-biphenyl and bishidroxymethyl-biphenyl reacted under alkaline
Heterocyclic Synthesis via Enaminones: Synthesis and Molecular Docking Studies of Some Novel Heterocyclic Compounds Containing Sulfonamide Moiety  [PDF]
Ahmed Abd El-Hameed Hassan
International Journal of Organic Chemistry (IJOC) , 2014, DOI: 10.4236/ijoc.2014.41009
Abstract: 4-Acetyl-N, N-diethylbenzenesulfonamide (1) was condensed with dimethylformamide dimethy-lacetal (DMF-DMA) to yield the enaminone, which reacts readily with different reagents to give the corresponding pyrazoles, triazolopyrimidine, imidazopyridine, pyrimidopyrimidine, pyrazolopyrimidine, benzofuran, pyranone, pyridine, pyrimidine and pyrazolopyridazine derivatives. These compounds were designed to comply with the general features of sulfonamide pharmacophore which act as Cyclooxygenase (COX-2) inhibitors. Virtual screening using molecular docking studies of the synthesized compounds was performed by (MOE), the molecular docking results indicate that, some synthesized compounds suitable inhibitor against (COX-2) with further modification.
Quantum Chemical and Experimental Studies on the Mechanism of Alkylation of β-Dicarbonyl Compounds. The Synthesis of Five and Six Membered Heterocyclic Spiro Derivatives  [PDF]
Nurettin Sadikov,Sahin Nasibov,Cemil Ogretir,Halil Berber,Ali Hüseyinli
Molecules , 2004, DOI: 10.3390/91100922
Abstract: The alkylation of β-dicarbonyl compounds in a K2CO3/DMSO system wasfound to afford O- and C-alkylated derivatives, depending on the type of the β-dicarbonylcompound involved. The alkyl derivatives obtained were used in the synthesis of some newspiro barbituric acid derivatives. Quantum chemical calculations were carried out toelucidate the reaction mechanisms for some typical synthesis.
Benzylidene-bis-(4-Hydroxycoumarin) and Benzopyrano-Coumarin Derivatives: Synthesis, 1H/13C-NMR Conformational and X-ray Crystal Structure Studies and In Vitro Antiviral Activity Evaluations  [PDF]
Davorka Zavr?nik,Samija Muratovi?,Damjan Makuc,Janez Plavec,Mario Cetina,Ante Nagl,Erik De Clercq,Jan Balzarini,Mladen Mintas
Molecules , 2011, DOI: 10.3390/molecules16076023
Abstract: We report on the synthesis of 4-hydroxycoumarin dimers 1–15 bearing an aryl substituent on the central linker and fused benzopyranocoumarin derivatives 16–20 and on their in vitro broad anti-DNA and RNA virus activity evaluations. The chemical identities and structure of compounds 1–20 were deduced from their homo- and heteronuclear NMR measurements whereas the conformational properties of 5, 14 and 20 were assessed by the use of 1D difference NOE enhancements. Unequivocal proof of the stereostructure of compounds 7, 9, 16 and 18 was obtained by single crystal X-ray diffraction method. The X-ray crystal structure analysis revealed that two 4-hydroxycoumarin moieties in the 4-trifluoromethylphenyl- and 2-nitrophenyl derivatives (compounds 7 and 9, respectively) are intramolecularly hydrogen-bonded between hydroxyl and carbonyl oxygen atoms. Consequently, the compounds 7 and 9 adopt conformations in which two 4-hydroxy-coumarin moieties are anti-disposed. Antiviral activity evaluation results indicated that the 4-bromobenzylidene derivative of bis-(4-hydroxycoumarin) (compound 3) possesses inhibitory activity against HSV-1 (KOS), HSV-2 (G), vaccinia virus and HSV-1 TK- KOS (ACVr) at a concentration of 9–12 μM and at a minimum cytotoxic concentration (MCC) greater than 20 μM. Compounds 4–6, 8, and 20 were active against feline herpes virus (50% effective concentration, EC50 = 5–8.1 μM), that is at a 4-7-fold lower concentration than the MCC.
Metal-Based Biologically Active Compounds: Synthesis, Spectral, and Antimicrobial Studies of Cobalt, Nickel, Copper, and Zinc Complexes of Triazole-Derived Schiff Bases  [PDF]
Kiran Singh,Yogender Kumar,Parvesh Puri,Chetan Sharma,Kamal Rai Aneja
Bioinorganic Chemistry and Applications , 2011, DOI: 10.1155/2011/901716
Abstract: A series of cobalt, nickel, copper, and zinc complexes of bidentate Schiff bases derived from the condensation reaction of 4-amino-5-mercapto-3-methyl/ethyl-1,2,4-triazole with 2,4-dichlorobenzaldehyde were synthesized and tested as antimicrobial agents. The synthesized Schiff bases and their metal complexes were characterized with the aid of elemental analyses, magnetic moment measurements, spectroscopic and thermogravimetric techniques. The presence of coordinated water in metal complexes was supported by infrared and thermal gravimetric studies. A square planar geometry was suggested for Cu(II) and octahedral geometry proposed for Co(II), Ni(II), and Zn(II) complexes. The Schiff bases and their metal complexes have been screened for antibacterial (Pseudomonas aeruginosa, Bacillus subtilis) and antifungal activities (Aspergillus niger, A. flavus). The metal complexes exhibited significantly enhanced antibacterial and antifungal activity as compared to their simple Schiff bases. 1. Introduction Of late due to the constant emergence of antibiotics resistance to clinically used compounds, it is the need of the hour to develop novel antibiotics classes, which eventually would target the lipoid layer of the organisms and other aspects of pathogens’ life cycle. Metal complexes may be subjected for the design and synthesis of such possibilities having such biological activities [1–3]. The chemistry of Schiff bases and their structural analogues has occupied a place of considerable importance [4] as they easily form stable complexes with most transition metal ions [5, 6] and well-established biological properties. 1,2,4-triazoles nucleus and their derivatives emerge rapidly with the advances of modern heterocyclic chemistry, promising a variety of medical applications such as antibacterial, antifungal, anticancer, antitumor, anticonvulsant, anti-inflammatory, and analgesic properties [7–12]. Schiff bases of 1,2,4-triazoles find diverse applications and extensive biological activity. The incorporation of the 1,2,4-triazole unit into Schiff base macrocycles is of considerable current interest as complexes of 1,2,4-triazoles are being developed for potential use in applications such as magnetic materials and photo chemically driven molecular devices [13]. Schiff bases derived from 3-substituted-4-amino-5-mercapto-1,2,4-triazoles show analgesic, antimicrobial, anti-inflammatory, and antidepressant activities [14]. The aim of the present study was to modify the bioactivities of 1,2,4-triazole Schiff bases and gain the relative derivatives with better curing
Synthesis and thermal studies of solid state 2-chloro-benzylidenepyruvic acid and its compounds with sodium, aluminium (III), gallium (III) and indium (III) cations
Bannach, G.;Schnitzler, E.;Melios, C. B.;Ionashiro, M.;
Eclética Química , 2004, DOI: 10.1590/S0100-46702004000100004
Abstract: the synthesis of sodium 2-chlorobenzylidenepyruvate and its corresponding acid as well as binary, binary together with it's acid or hydroxo-2-chorobenzylidenepyruvate of aluminium (iii), gallium (iii) and indium (iii), were isolated. chemical analysis, thermogravimetry, derivative thermogravimetry (tg/dtg), simultaneous thermogravimetry-differential thermal analysis (tg-dta) and x-ray powder diffractometry have been employed to characterize and to study the thermal behaviour of these compounds. the results provided information concerning the stoichiometry, crystallinity, thermal stability and thermal decomposition.
Synthesis and Antiviral Activity of Conformational Analogues of Leucamide A  [PDF]
Wen-Long Wang,Hai-Jun Chen,Wei-Ping Ma,Min Gu,Min-Zhi Fan,Jing-Ya Li,Bainian Feng,Fa-Jun Nan
Molecules , 2012, DOI: 10.3390/molecules171214522
Abstract: In order to study the effect of heterocyclic core conformational state of leucamide A on its anti-influenza virus A activity, five conformational analogues were prepared by replacing the Pro-Leu dipeptide in the molecule with various amino acids. The amino acids used were of 2 to 6 carbons. The results showed that these replacements not only changed the conformational relationship between the 4,2-bisheterocycle tandem pair and the third heterocycle, but also had dramatic effect on its activity against influenza virus A.
International Journal of Drug Discovery , 2011,
Abstract: In past few years the use of organometallics in medicinal purpose takes the full attention of researchers to work inthis field. The present work deals the synthesis of some new organobismuth amides having a pyramidal geometry asresulted by their characterization with the help of different techniques along with spectral analysis. The compounds are alsoscreened for their biological studies against different bacterial and fungal strains along with human breast adenocarcinomaand mammary cancer cell lines in-vitro and the results are surprising that these compounds plays significant role inbiomedicinal activities.
Synthesis, electrochemical, spectrophotometric and potentiometric studies of two azo-compounds derived from 4-amino-2-methylquinoline in ethanolic-aqueous buffered solutions
El-Attar, Mona A.;Ismail, Iqbal M.;Ghoneim, Mohamed M.;
Journal of the Brazilian Chemical Society , 2012, DOI: 10.1590/S0103-50532012005000013
Abstract: two azo-compounds, 2-methyl-4-(5-amino-2-hydroxy-phenylazo)-quinoline (2) and 2-methyl-4-(2-hydroxy-5-nitrophenylazo)-quinoline, derived from 4-amino-2-methylquinoline were synthesized. their chemical structures were characterized and confirmed by means of elemental chemical analysis, infrared (ir) spectroscopy, 1h nuclear magnetic resonance (nmr) and mass spectrometry (ms). the electrochemical behavior of the starting compound (4-amino-2-methylquinoline) and of the two synthesized azo-derivatives was studied at the mercury electrode in the b-r universal buffer at various ph values (2-11.5) containing 40% (v/v) ethanol using dc-polarography, cyclic voltammetry and controlled-potential coulometry. their electrode reaction pathways were elucidated and discussed. the dissociation constants (pka) of the examined compounds, stability constants and stoichiometry of their complexes in solution with some transition metal ions (co(ii), ni(ii), cu(ii), la(iii) and uo22+) were determined.
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