- Optimization of Artificial Siderophores as 68Ga-Complexed PET Tracers for in Vivo Imaging of Bacterial Infections
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The diagnosis of bacterial infections at deep body sites benefits from noninvasive imaging of molecular probes that can be traced by positron emission tomography (PET). We specifically labeled bacteria by targeting their iron transport system with artificial siderophores. The cyclen-based probes contain different binding sites for iron and the PET nuclide gallium-68. A panel of 11 siderophores with different iron coordination numbers and geometries was synthesized in up to 8 steps, and candidates with the best siderophore potential were selected by a growth recovery assay. The probes [68Ga]7 and [68Ga]15 were found to be suitable for PET imaging based on their radiochemical yield, radiochemical purity, and complex stability in vitro and in vivo. Both showed significant uptake in mice infected with Escherichia coli and were able to discern infection from lipopolysaccharide-triggered, sterile inflammation. The study qualifies cyclen-based artificial siderophores as readily accessible scaffolds for the in vivo imaging of bacteria.
- Peukert, Carsten,Langer, Laura N. B.,Wegener, Sophie M.,Tutov, Anna,Bankstahl, Jens P.,Karge, Bianka,Bengel, Frank M.,Ross, Tobias L.,Br?nstrup, Mark
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p. 12359 - 12378
(2021/09/02)
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- Antibiotic Conjugates with an Artificial MECAM-Based Siderophore Are Potent Agents against Gram-Positive and Gram-Negative Bacterial Pathogens
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The development of novel drugs against Gram-negative bacteria represents an urgent medical need. To overcome their outer cell membrane, we synthesized conjugates of antibiotics and artificial siderophores based on the MECAM core, which are imported by bacterial iron uptake systems. Structures, spin states, and iron binding properties were predicted in silico using density functional theory. The capability of MECAM to function as an effective artificial siderophore in Escherichia coli was proven in microbiological growth recovery and bioanalytical assays. Following a linker optimization focused on transport efficiency, five β-lactam and one daptomycin conjugates were prepared. The most potent conjugate 27 showed growth inhibition of Gram-positive and Gram-negative multidrug-resistant pathogens at nanomolar concentrations. The uptake pathway of MECAMs was deciphered by knockout mutants and highlighted the relevance of FepA, CirA, and Fiu. Resistance against 27 was mediated by a mutation in the gene encoding ExbB, which is involved in siderophore transport.
- Br?nstrup, Mark,Grunenberg, J?rg,Hotop, Sven-Kevin,Karge, Bianka,Lai, Yi-Hui,Peukert, Carsten,Pinkert, Lukas,Schulze, Lara Marie
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p. 15440 - 15460
(2021/10/25)
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- Novel quinolizidine salicylamide influenza fusion inhibitors
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A novel series of quinolizidine salicylamides was synthesized as specific inhibitors of the H1 subtype of influenza A viruses. These inhibitors inhibit the pH-induced fusion process, thereby blocking viral entry into host cells. Compound 16 was the most active inhibitor in this series with an EC50 of 0.25 μg/mL in plaque reduction assay. The synthesis and the SAR of these compounds are discussed.
- Yu, Kuo-Long,Ruediger, Edward,Luo, Guangxiang,Cianci, Christopher,Danetz, Stephanie,Tiley, Laurence,Trehan, Ashok K.,Monkovic, Ivo,Pearce, Bradley,Martel, Alain,Krystal, Mark,Meanwell, Nicholas A.
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p. 2177 - 2180
(2007/10/03)
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- 2-oxo-1-(((substituted sulfonyl)amino)-carbonyl)azetidines
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Antibacterial activity is exhibited by β-lactams having a 3-acylamino substituent and having in the 1-position an activating group of the formula STR1 wherein R is
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- Analogs of 3-(1-Phenyl-3-oxobutyl)-4-hydroxycoumarin (Warfarin) Prepared from Substituted Salicylic Acids
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Some derivatives of salicylic acid containing substituents meta to the carboxyl group were used to prepare analogs of the anticoagulant drug warfarin, 3-(1-phenyl-3-oxobutyl)-4-hydroxycoumarin, containing substituents in either the 6- or 8-position of the coumarin ring.When the substituent was the hydroxyl group, the resulting products are previously identified metabolites of warfarin.The substituted salicylic acid is first acetylated with acetic anhydride, then either converted to the acid chloride and condensed with diethyl malonate in the presence of sodium hydroxide or converted to the mixed anhydride with formic acid and condensed with ethoxymagnesium diethyl malonate to yield, in either case, the corresponding 3-carbethoxy-4-hydroxycoumarin substituted in the 6- or 8-position of the coumarin ring.These compounds readily condense with benzalacetone to form the corresponding substituted warfarin in the presence of 5 mole percent tertiary amine catalyst.This method offers an improved route for the synthesis or 8-hydroxywarfarin.
- Obaseki, Andrew O.,Steffen, James E.,Porter, William R.
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p. 529 - 533
(2007/10/02)
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