- Bispidine dioxotetraaza macrocycles: A new class of bispidines for 64Cu PET imaging
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The three new dioxo-tetraazamacrocyclic ligands with a fused, very rigid bispidine (3,7-diazabicyclo[3.3.1]nonane) group connecting the two tertiary amine donors, and ethyl, propyl, or benzene groups connecting the two amide donors are highly preorganized and lead to very stable, uncharged Cu II complexes. Solution spectroscopy and solid state structures indicate that these are square pyramidal with a solvent molecule occupying the apical position. Cyclic voltammetry defines a reversible CuIII/II couple and a strongly negative irreversible CuII/I couple (ca. -2 V vs Fc/Fc+), indicating that the CuII complexes are very stable in solution. This is supported by superoxide dismutase (SOD) and human serum challenge experiments as well as the biodistribution, which all show that the benzene-based ligand has the highest in vitro and in vivo stability and that this was expected on the basis of the macrocycle ring size and shape and the highest degree of preorganization. This ligand is easy to functionalize for a possible coupling to biological vector molecules and/or fluorescence markers for PET (positron emission tomography) and multimodal imaging (i.e., PET and optical imaging).
- Comba, Peter,Kubeil, Manja,Pietzsch, Jens,Rudolf, Henning,Stephan, Holger,Zarschler, Kristof
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- The Preparation of a Novel Corrosion Inhibitor and Its Corrosion Inhibition Behavior on 2024 Al-Cu-Mg Alloy in Acid Solution
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A new corrosion inhibitor was synthesized from chloroacetyl chloride, 1,3-propanediamine, and dodecyldimethyl tertiary amine. The structure of the synthesized product was characterized using Fourier transform infrared(FTIR). The critical micelle concentration (CMC) was determined from surface tension measurements. The inhibition behavior of the corrosion inhibitor for 2024 Al-Cu-Mg alloy was studied using the weight-loss method and electrochemical measurements in hydrochloric acid solution. Experimental results show: The CMC is 7.767 × 10?4 mol L?1 and IE (Cpro = 1 × 10?3 mol L?1) ≈ 87.9%. The adsorption free energy is calculated to be ?33.12 kJ mol?1. Therefore, the adsorption mode is more inclined to physical adsorption. When the concentration of the synthesized product is lower than the CMC, it satisfies the Langmuir adsorption model; when the concentration is higher than the CMC, it no longer follows the Langmuir adsorption model.
- Juan, Du,Shuai, Jia,Fan, Yang,Ziming, Wei,Haipeng, Song,Xudong, Yang,Fusheng, Wang
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- Synthesis and reactivity of the macrobicyclic complexes (1,5,8,12-tetraaza-17-oxabicyclo[10.5.2]-nonadecane)cobalt(III) perchlorate ([Co(L1)(CIO4)]-(CIO4)2), [(chloro(1,4,8,11-tetraaza-17-oxabicyclo-[9.5.3]nonadecane)cobalt(III) perchlorate ([Co(L2)-(CI)](CIO4)2)
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The potentially penta-coordinating ligands L2 and L3 have been synthesized by reaction of the 10-membered macrocycle 1,5-diaza-8-oxacyclodecane with either 1,9-dichloro-3,7-diazanonane-2,8-dione, and subsequent reduction of the diamide (3), or with 1,9-dichloro-3,7-(dimethyl) diazanonane-2,8-dione and reduction (L3)-. A similar procedure is outlined for the dimethylated macrobicycle (L4), based on the corresponding nine-membered 1,4-diaza-7-oxacyclononane. The Co(III) complexes of these ligands and of 1,5,8,12-tetraaza-17-oxabicyclo[10.5.2]nonadecane (L 1) have been prepared. Spectrophotometric determinations on the L1 complex ion confirm the presence of two hydrogen ion related equilibria, one of which (pK = 2.2 ± 0.2) is associated with the proposed replacement of the apical ether oxygen by a water molecule that is bound to the metal centre and hydrogen bonded to the ether. The species derived from L 1 and L2 exhibit remarkable kinetic stability. Studies on the anation of the [Co(L1)(H2O)](CIO4) 3 with chloride ions in acidic media are consistent with the reaction of both the proton-related complex and the [Co(L1)(H 2O)]3+ ion. Whilst complex ions containing two secondary NH groups maintain the metal-ion coordination in strongly acidic media, corresponding species with ligands containing all four tertiary amine sites are subject to attack by protons leading to a relatively facile demetallation of the complexes. The latter finding is supported by kinetic studies and mass spectrometric fragmentation patterns of the ions.
- Rodopoulos, Theo,Ishihara, Koji,Rodopoulos, Mary,Zaworotko,Maeder,McAuley
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- In Situ Cyclization of Native Proteins: Structure-Based Design of a Bicyclic Enzyme
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Increased tolerance of enzymes towards thermal and chemical stress is required for many applications and can be achieved by macrocyclization of the enzyme resulting in the stabilizing of its tertiary structure. Thus far, macrocyclization approaches utilize a very limited structural diversity, which complicates the design process. Herein, we report an approach that enables cyclization through the installation of modular crosslinks into native proteins composed entirely of proteinogenic amino acids. Our stabilization procedure involves the introduction of three surface-exposed cysteine residues, which are reacted with a triselectrophile, resulting in the in situ cyclization of the protein (INCYPRO). A bicyclic version of sortase A was designed that exhibits increased tolerance towards thermal as well as chemical denaturation, and proved to be efficient in protein labeling under denaturing conditions. In addition, we applied INCYPRO to the KIX domain, resulting in up to 24 °C increased thermal stability.
- Pelay-Gimeno, Marta,Bange, Tanja,Hennig, Sven,Grossmann, Tom N.
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- Design, synthesis and biological evaluation of organophosphorous-homodimers as dual binding site acetylcholinesterase inhibitors
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The cluster effect is an effective strategy to explore new lead compounds, and has been successfully applied in rational drug design and screening. A series of novel organophosphorous-homodimers were designed and synthesized based on the dual-site structure characteristics of acetylcholinesterase (AChE). The compounds were evaluated in vitro for their inhibitory activity to AChE extracted from Drosophila melanogaster and Musca domestic. Compound 4H showed an excellent inhibitor activity to both Drosophila melanogaster and Musca domestic with the corresponding IC50 values of 23 and 168 nM, respectively. Meanwhile, its activities against Drosophila melanogaster and Musca domestic AChE were more than 10,00,000 and 100,000-fold higher compared with the parent compound (MH), and was up to 245 and 107-fold higher than those of the positive control omethoate. The molecular docking study revealed that 4H possessed an optimal spacer length and can perfectly fit into the central pocket, active gorge, and peripheral site of DmAChE, and consequently exhibited highly improved inhibitor potency to DmAChE. The bioassay tests showed that 4 series compounds showed prominent insecticidal activities against both Lipaphser erysimi and Tetranychus cinnbarinus at a concentration of 200 mg/L. The insecticide activity of compound 4H was particularly significant that can cause 96% mortality to Tetranychus cinnbarinus after 24 h of treatment.
- Xie, Ruliang,Zhao, Qianfei,Zhang, Tao,Fang, Jing,Mei, Xiangdong,Ning, Jun,Tang, Yun
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- Bivalent organophosphorus compounds - Synthesis and acetylcholinesterase inhibitory activity
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A series of novel symmetric S,S′-2,2′-(ethane-1,2- diylbis(azanediyl)) bis(2-oxoethane-2,1-diyl) O,O,O′,O′-tetraethyl diphosphorodithioate derivatives (12) was designed and synthesized based on the cluster effect and the multiple binding sites of acetylcholinesterase (AChE). The structures of all the newly synthesized title compounds were characterized by 1 H and 13 C NMR as well as elemental analyses. Their inhibitory activities against AChE were tested, and compound 12b exhibited the best activity (6.60-fold higher than ethion). The results suggested that the compound would bind to the catalytic center and the narrow gorge of the AChE simultaneously. Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional table.
- Xie, Ruliang,Zhang, Ting,Zhao, Qianfei,Zhang, Tao,Mei, Xiangdong,Yuan, Huizhu,Ning, Jun
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- New high yield syntheses of cyclams using the crab-like cyclization reaction
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A new high yield method to synthesize cyclams containing one or two unsubstituted ring nitrogen atoms and with alkyl groups on the remaining ring nitrogen atoms is presented. The method consists of the ring closure reaction of a crab-like bis-α-chloroamide with a bis-secondary amine followed by reduction. The amide functions of the starting material act as protecting groups for the protons on the amide nitrogen atoms.
- Bradshaw,Krakowiak,Izatt,Zamecka-Krakowiak
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- BIODEGRADABLE POLYIMIDAZOLIUMS AND OLIGOIMIDAZOLIUMS
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Disclosed herein are compounds in the form of polymers, oligomers and defined molecules having repeating units that all incorporate repeating units formed from an imidazolium group and a biodegradable chain connected to an adjacent repeating unit. The com
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- COMPOUNDS FOR THE TREATMENT OF MYOTONIC DYSTROPHY
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The present invention relates to a compound of formula (I), provided that this compound is not caffeine, for use in the treatment of myotonic dystrophy type 1 and type 2. The present invention also relates to compositions comprising the compound of formula (I). The present invention further relates to new compounds which are dimers of compounds of formula (I).
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(2016/06/13)
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- Synthesis of α-chloroamides in water
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The reaction between chloroacetyl chloride and mono- or bis-aliphatic or aromatic amines in water under basic or neutral conditions gives rise to the formation of a variety of functionalized α-chloroamides. The resulting products were obtained as solids in moderate to good yields, upon precipitation and isolation by filtration.
- Harte, Andrew J.,Gunnlaugsson, Thorfinnur
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p. 6321 - 6324
(2007/10/03)
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- Synthesis and characterisation of bis-cyclen based dinuclear lanthanide complexes
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The design and synthesis of several bis-macrocyclic cyclen (1,4,7,10-tetraazacyclododecane) ligands and their corresponding lanthanum or europium complexes is described; these dinuclear lanthanide systems were made by connecting two macrocyclic cyclen moi
- Gunnlaugsson, Thorfinnur,Harte, Andrew J.
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p. 1572 - 1579
(2008/02/03)
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