- Strategically designed azolyl-carboxylate MOFs for potential humid CO2 capture
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Development of solid sorbents with optimal CO2 capture characteristics is key to improving the efficiency of PSA based CO2 separation. Of the several potential sorbents, metal organic frameworks (MOFs) hold a key niche. This is owing to their modular tunable structures and manipulatable adsorption sites. Yet, developing a MOF that meets the multiple demands of a gas-separation sorbent remains a challenge. Particularly, tuning them to adsorb CO2 over the more polar water is quite difficult. The presence of highly polarizing metal centers and oxygen-rich sites in MOFs makes it difficult to retain their CO2 adsorption capacities under humid gas streams. However, tailoring the organic framework to incorporate humid CO2 capture properties should be feasible. Along these lines, here we have developed a family of iso-structural MOFs built from bi-functional ligands that carry basic azolyl and chelating carboxylate groups together. Importantly, the framework is built by employing acetate moieties as ‘modulators’; they provide a hydrophobic lining to the pore-walls. This not only enables selective adsorption of CO2, but also helps retain about 80% of the capture capacity even upon exposure to 75% RH. Along with its other advantageous features: high CO2 uptake and selectivity (3 mmol g?1 and s(CO2-N2) = ~500 for 85N2?:?15CO2@303 K); surface area: ~700 m2 g?1, working capacity: 2.6 mmol g?1; optimal HOA (22-30 kJ mol?1) and CO2 kinetics (Dc = 1.02 × 10?8 m2 s?1), these MOFs can qualify as efficient candidates for humid CO2 capture. Furthermore, we identify the most-favorable CO2 adsorption sites via simulated annealing methods, from which the presence of polarized CO2 molecules located adjacent to the π-electron rich pore walls can be seen. Importantly, these polarized molecules form T-shaped configurations among themselves via C(δ+ve)?O(δ?ve) interactions resembling those found in solid CO2, a cooperative feature that is not observed in the other CO2 molecules in the structure, which are not proximal to the polarizing walls.
- Nandi, Shyamapada,Haldar, Sattwick,Chakraborty, Debanjan,Vaidhyanathan, Ramanathan
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- Oxidation of Primary Alcohols and Aldehydes to Carboxylic Acids via Hydrogen Atom Transfer
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The oxidation of primary alcohols and aldehydes to the corresponding carboxylic acids is a fundamental reaction in organic synthesis. In this paper, we report a new chemoselective process for the oxidation of primary alcohols and aldehydes. This metal-free reaction features a new oxidant, an easy to handle procedure, high isolated yields, and good to excellent functional group tolerance even in the presence of vulnerable secondary alcohols and tert-butanesulfinamides.
- Tan, Wen-Yun,Lu, Yi,Zhao, Jing-Feng,Chen, Wen,Zhang, Hongbin
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supporting information
p. 6648 - 6653
(2021/09/08)
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- Fragment-Based Discovery of a Qualified Hit Targeting the Latency-Associated Nuclear Antigen of the Oncogenic Kaposi's Sarcoma-Associated Herpesvirus/Human Herpesvirus 8
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The latency-associated nuclear antigen (LANA) is required for latent replication and persistence of Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8. It acts via replicating and tethering the virus episome to the host chromatin and exerts other functions. We conceived a new approach for the discovery of antiviral drugs to inhibit the interaction between LANA and the viral genome. We applied a biophysical screening cascade and identified the first LANA binders from small, structurally diverse compound libraries. Starting from a fragment-sized scaffold, we generated optimized hits via fragment growing using a dedicated fluorescence-polarization-based assay as the structure-activity-relationship driver. We improved compound potency to the double-digit micromolar range. Importantly, we qualified the resulting hit through orthogonal methods employing EMSA, STD-NMR, and MST methodologies. This optimized hit provides an ideal starting point for subsequent hit-to-lead campaigns providing evident target-binding, suitable ligand efficiencies, and favorable physicochemical properties.
- Kirsch, Philine,Jakob, Valentin,Oberhausen, Kevin,Stein, Saskia C.,Cucarro, Ivano,Schulz, Thomas F.,Empting, Martin
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supporting information
(2019/05/01)
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- Fragment-Based Discovery of a Qualified Hit Targeting the Latency-Associated Nuclear Antigen of the Oncogenic Kaposi's Sarcoma-Associated Herpesvirus/Human Herpesvirus 8
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The latency-associated nuclear antigen (LANA) is required for latent replication and persistence of Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8. It acts via replicating and tethering the virus episome to the host chromatin and exerts other functions. We conceived a new approach for the discovery of antiviral drugs to inhibit the interaction between LANA and the viral genome. We applied a biophysical screening cascade and identified the first LANA binders from small, structurally diverse compound libraries. Starting from a fragment-sized scaffold, we generated optimized hits via fragment growing using a dedicated fluorescence-polarization-based assay as the structure-activity-relationship driver. We improved compound potency to the double-digit micromolar range. Importantly, we qualified the resulting hit through orthogonal methods employing EMSA, STD-NMR, and MST methodologies. This optimized hit provides an ideal starting point for subsequent hit-to-lead campaigns providing evident target-binding, suitable ligand efficiencies, and favorable physicochemical properties.
- Kirsch, Philine,Jakob, Valentin,Oberhausen, Kevin,Stein, Saskia C.,Cucarro, Ivano,Schulz, Thomas F.,Empting, Martin
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supporting information
p. 3924 - 3939
(2019/05/06)
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- An NMR-guided screening method for selective fragment docking and synthesis of a warhead inhibitor
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Selective hits for the glutaredoxin ortholog of Brucella melitensis are determined using STD NMR and verified by trNOE and 15N-HSQC titration. The most promising hit, RK207, was docked into the target molecule using a scoring function to compare simulated poses to experimental data. After elucidating possible poses, the hit was further optimized into the lead compound by extension with an electrophilic acrylamide warhead. We believe that focusing on selectivity in this early stage of drug discovery will limit cross-reactivity that might occur with the human ortholog as the lead compound is optimized. Kinetics studies revealed that lead compound 5 modified with an ester group results in higher reactivity than an acrylamide control; however, after modification this compound shows little selectivity for bacterial protein versus the human ortholog. In contrast, hydrolysis of compound 5 to the acid form results in a decrease in the activity of the compound. Together these results suggest that more optimization is warranted for this simple chemical scaffold, and opens the door for discovery of drugs targeted against glutaredoxin proteins-a heretofore untapped reservoir for antibiotic agents.
- Khattri, Ram B.,Morris, Daniel L.,Davis, Caroline M.,Bilinovich, Stephanie M.,Caras, Andrew J.,Panzner, Matthew J.,Debord, Michael A.,Leeper, Thomas C.
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- 3D printing of a heterogeneous copper-based catalyst
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One of the most important environmental challenges of modern society is to develop new catalysts that make possible chemical processes with reduced environmental impact. Catalyst immobilization is an appealing strategy that, in addition to facilitating catalyst recovery, has proved to give higher catalytic performance, since the solid support usually provides chemical, thermal, and mechanical stabilization to the catalytic species. In this work Cu/Al2O3 catalytic system with a woodpile porous structure is synthesized by 3D printing and then sintered at high temperature to generate a copper-supported rigid structure with high mechanical strength, a high surface-to-volume ratio, and controlled porosity. The catalytic species (Cu) are immobilized in the Al2O3 matrix to avoid the leaching of the metal into the reaction medium. Al2O3 was selected because it is a good material to obtain a structure with high mechanical stability after high-temperature treatment. The resulting device shows high catalytic efficacy and good recyclability and did not produce leaching of copper to the reaction medium in different Ullmann reactions. Ease of preparation, excellent reactivity, recyclability, and negligible metal contamination all make the 3D printing technique a good strategy for fabricating other types of metal/oxide heterogeneous catalytic systems.
- Tubío, Carmen R.,Azuaje, Jhonny,Escalante, Luz,Coelho, Alberto,Guitián, Francisco,Sotelo, Eddy,Gil, Alvaro
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p. 110 - 115
(2016/01/09)
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- Magnetically retrievable lepidocrocite supported copper oxide nanocatalyst (Fe-CuO) for N-arylation of imidazole
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A simple and efficient lepidocrocite-supported copper oxide catalyst (Fe-CuO) has been successfully prepared by a simple precipitation method in aqueous medium from readily available inexpensive starting materials and was used as a heterogeneous nanocatal
- Sivakami,Babu, S. Ganesh,Dhanuskodi,Karvembu
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p. 8571 - 8578
(2015/03/03)
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- Palladium(II) 9,10-phenanthrenequinone N-substituted thiosemicarbazone/semicarbazone complexes as efficient catalysts for N-arylation of imidazole
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A series of palladium complexes, [PdCl(L1-4)] (1-4) (L1 = 9,10-phenanthrenequinone thiosemicarbazone, L2 = 9,10-phenanthrenequinone methylthiosemicarbazone, L3 = 9,10-phenanthrenequinone phenylthiosemicarbazone, and L4 = 9,10-phenanthrenequinone semicarbazone), have been synthesized and characterized by elemental analyses, UV-vis, FT-IR, 1H and 13C NMR, and ESI-Mass spectroscopic methods. The catalytic efficiency of the synthesized complexes was examined against N-arylation of imidazole. The system works well with the electron-rich, -neutral, and -deficient aryl halides to afford the products in good to excellent yields. Sterically congested aryl halides and heteroaryl halides have also been used as substrates to provide N-arylated heterocycles. In addition, this methodology can be applicable to other substrates with N-containing heterocycles.
- Anitha, Panneerselvam,Manikandan, Rajendran,Viswanathamurthi, Periasamy
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p. 3537 - 3550
(2015/09/28)
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- Novel binuclear palladium(II) complexes of 2-oxoquinoline-3-carbaldehyde Schiff bases: Synthesis, structure and catalytic applications
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A series of novel binuclear Pd(II) complexes of the type [(PPh 3)2ClPd(L)PdCl] [where L = dianionic bridged ligands derived from 2-oxo-1,2-dihydroquinoline-3-carbaldehyde or its derivatives with o-aminophenol/o-aminothiophenol] have been reported. The new complexes have been characterized by elemental analysis, FT-IR, UV-Vis and NMR (1H and 31P) spectroscopic techniques. The coordination mode of the ligands and the geometry of the complexes were confirmed by single crystal X-ray crystallography of one of the complexes. The catalytic efficiency of one of the binuclear Pd(II) complexes was tested for N-arylation of imidazole.
- Priyarega, Sivakumar,Senthil Raja, Duraisamy,Ganesh Babu, Sundaram,Karvembu, Ramasamy,Hashimoto, Takeshi,Endo, Akira,Natarajan, Karuppannan
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experimental part
p. 143 - 148
(2012/04/11)
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- Cu-Al hydrotalcite: An efficient and reusable ligand-free catalyst for the coupling of aryl chlorides with aliphatic, aromatic, and N(H)-heterocyclic amines
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Copper-aluminum hydrotalcite catalysts were effectively used in the coupling of aryl chlorides with aliphatic, aromatic, and N(H)-heterocyclic amines to afford the corresponding N-alkylated/arylated amines in excellent yields. The catalyst was quantitatively recovered from the reaction by simple filtration and reused for a number of cycles with almost consistent activity. Georg Thieme Verlag Stuttgart.
- Sreedhar,Arundhathi,Linga Reddy,Amarnath Reddy,Lakshmi Kantam
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experimental part
p. 2517 - 2522
(2010/03/24)
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- Sulfonamide derivatives, their production and use
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The present invention provides compounds which specifically inhibit FXa, which are effective when orally administered and which are useful as a safe medicine for the prevention or treatment of diseases caused by thrombus or infarction. Compounds of this invention are piperazinones of the formula: wherein R1is an optionally substituted hydrocarbon group or an optionally substituted heterocyclic group; the ring A is an optionally substituted divalent nitrogen-containing heterocyclic group, in addition to being substituted by the group of the formula: and the group of the formula: Y is an optionally substituted divalent hydrocarbon group or an optionally substituted divalent heterocyclic group; X is a direct bond or an optionally substituted alkylene chain; Z is (1) an amino group substituted with an optionally substituted hydrocarbon group, (2) an optionally substituted imino group or (3) an optionally substituted nitrogen-containing heterocyclic group; provided that when X is a direct bond and Z is an optionally substituted 6-membered nitrogen-containing aromatic heterocyclic group, Y is an optionally substituted divalent hydrocarbon group or an optionally substituted divalent unsaturated heterocyclic group; or a salt thereof.
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Referential example 16
(2010/11/29)
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- Amide derivatives as 5HT1D receptor antagonists
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Novel amide derivatives, processes for their preparation, and pharmaceutical compositions containing them are disclosed.
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