- Total synthesis of cytotoxic metabolite (±)-desmethyldiaportinol from Ampelomyces sp.
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A concise total synthesis of (±)-desmethyldiaportinol isolated from Ampelomyces sp. is described. Microwave-assisted cyclocondensation of 3,5-dimethoxyhomopthalic acid with 3,4-dibromobutanoyl chloride afforded the 3-(2,3-dibromopropyl)-6, 8-dimethoxyisocoumarin in 2-3 min as the pivotal step. The 3,4-dibromobutanoyl chloride was itself synthesised from 3-butenoic acid via bromination in carbon tetrachloride at room temperature to yield 3,4-dibromobutanoic acid followed by reaction with thionyl chloride. The replacement of bromo-by hydroxyl substituent was achieved under mild conditions involving the refluxing in a mixture of acetone and water to provide (±)-3-(2,3-dihydroxypropyl)-6,8-dimethoxyisocoumarin which on complete demethylation furnished the title natural product.
- Saeed, Aamer,Qasim, Muhammad
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Read Online
- Benzamide derivatives targeting the cell division protein ftsz: Modifications of the linker and the benzodioxane scaffold and their effects on antimicrobial activity
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Filamentous temperature-sensitive Z (FtsZ) is a prokaryotic protein with an essential role in the bacterial cell division process. It is widely conserved and expressed in both Gram-positive and Gram-negative strains. In the last decade, several research g
- Casiraghi, Andrea,De Giuli Morghen, Carlo,Hrast, Martina,Radaelli, Antonia,Sebastián-Pérez, Victor,Straniero, Valentina,Suigo, Lorenzo,Valoti, Ermanno,Zanotto, Carlo,Zdovc, Irena
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- Phase-vanishing reactions with ptfe (teflon) as a phase screen
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Phase-vanishing reactions are triphasic reactions, which involve a reagent, a liquid perfluoroalkane, and a substrate. In a phase-vanishing reaction with PTFE tape as the phase screen instead of a liquid perfluoroalkane, there is no limitation related to the density of a phase and the denser phase can be in the top layer. The reactions were faster compared to traditional PV reactions, and it was possible to carry out sequential and tandem reactions and reactions under a reflux.
- Van Zee, Nathan J.,Dragojlovic, Veljko
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supporting information; experimental part
p. 3190 - 3193
(2009/11/30)
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- Solvent-free phase-vanishing reactions with PTFE (Teflon) as a phase screen
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In a solvent-free phase-vanishing reaction with PTFE (polytetrafluoroethylene, Teflon) tape as the phase screen, a thermometer adapter is utilized to insert a PTFE-sealed tube into the vapor phase above the substrate. Besides avoiding use of solvents, the experimental design is not dependent upon the densities of the reactants and the procedure generates little or no waste while providing the reaction products in high yield and in high purity.
- Pels, Kevin,Dragojlovic, Veljko
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scheme or table
(2010/04/22)
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- Tissue Distribution Properties of Technetium-99m-Diamide-Dimercaptide Complexes and Potential Use as Renal Radiopharmaceuticals
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A series of new ligands and the corresponding technetium-99m chelates based on diamide dimercaptide donor groups were synthesized as derivatives of technetium-99m 1,2-bis(2-thioacetamido)ethane, a complex shown to be excreted by renal tubular secretion. Chelation with 99mTc resulted in single radiochemical products or the expected numbers of stereoisomers. They were purified by high-performance liquid chromatography (HPLC) and evaluated in mice as potential renal tubular function agents. The in vivo properties were sensitive to the presence of functional groups, the positional isomerism of the carboxylate group functionality, and the chelate ring stereochemistry of the ligand. The presence of methyl groups slowed renal transit and decreased renal specificity. Cyclohexyl rings fused to the ethylene bridge of the center chelate ring decreased renal excretion while aromatic rings essentially abolished renal excretion. Slow hepatobiliary clearance was observed as an alternate mode of excretion. Polar groups, such as hydroxyl, carboxylate, and carboxamide, increased renal excretion rates and specificity in a stereochemically dependent manner. 99mTc chelates of 1,3-bis(2-thioacetamido)-2-hydroxypropane, 3,4-bis(2-thioacetamido)butanoate and 1,8-dimercapto-2,7-dioxo-3,6-diazanonanoate were identified as promising new renal radiopharmaceuticals.
- Kasina, Sudhakar,Fritzberg, Alan R.,Johnson, Dennis L.,Eshima, Dennis
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p. 1933 - 1940
(2007/10/02)
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