| 1. |
- Fan, Yanmiao, et al.
(författare)
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Detection of gemcitabine metabolism using 19F-NMR and its impacts on E. coli morphology
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- 19F-NMR spectroscopy is a sensitive analytical method to detect the metabolism of fluorine-containing drugs by bacteria. In this study, 19F-NMR was used to achieve the real time detection of metabolic process of gemcitabine (2′, 2′-difluorodeoxycytidine) by Escherichia Coli (E. coli) in the nutrient broth. Both E. coli and Staphylococcus aureus (S. aureus) were used in the metabolism study. E. coli can metabolize gemcitabine, while gemcitabine cannot be metabolized by S. aureus. Our results showed that gemcitabine can be totally metabolized to its inactive form 2′, 2′-difluorodeoxyuridine (dFdU) by E. coli both in Mueller-Hinton broth and M9 minimal salt. The metabolic rate of gemcitabine has a positive correlation with the bacterial concentrations. The metabolism is due to the presence of bacterial cytidine deaminase, and the enzyme inhibitor tetrahydrouridine (THU) can inhibit the gemcitabine metabolism. Scanning electron microscope (SEM) was used to study the effects of gemcitabine metabolism on E. coli morphological changes, and the treated E. coli was 2-3 times longer than the normal bacteria. 19F–NMR was capable to achieve real time detection of gemcitabine metabolism process considering there was no need to separate the bacterial cells from the nutrient medium, this study provided a fast and facile way to detect fluorine-containing drug metabolism by bacteria.
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| 2. |
- Ren, Yansong, 1988-, et al.
(författare)
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Configurational and Constitutional Dynamics of Enamine Molecular Switches
- 2020
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 26:67, s. 15654-15663
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Tidskriftsartikel (refereegranskat)abstract
- Dual configurational and constitutional dynamics in systems based on enamine molecular switches has been systematically studied. pH-responsive moieties, such as 2-pyridyl and 2-quinolinyl units, were required on the „stator“ part, also providing enamine stability through intramolecular hydrogen-bonding (IMHB) effects. Upon protonation or deprotonation, forward and backward switching could be rapidly achieved. Extension of the stator π-system in the 2-quinolinyl derivative provided a higher E-isomeric equilibrium ratio under neutral conditions, pointing to a means to achieve quantitative forward/backward isomerization processes. The „rotor“ part of the enamine switches exhibited constitutional exchange ability with primary amines. Interestingly, considerably higher exchange rates were observed with amines containing ester groups, indicating potential stabilization of the transition state through IMHB. Acids, particularly BiIII, were found to efficiently catalyze the constitutional dynamic processes. In contrast, the enamine and the formed dynamic enamine system showed excellent stability under basic conditions. This coupled configurational and constitutional dynamics expands the scope of dynamic C−C and C−N bonds and potentiates further studies and applications in the fields of molecular machinery and systems chemistry.
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| 3. |
- Ren, Yansong, 1988-, et al.
(författare)
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Multienzymatic cascade synthesis of an enantiopure (2R,5R)-1,3-oxathiolane anti-HIV agent precursor
- 2019
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Ingår i: Molecular Catalysis. - : Elsevier. - 2468-8274 .- 2468-8231. ; 468, s. 52-56
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Tidskriftsartikel (refereegranskat)abstract
- An enantiopure (2R,5R)-1,3-oxathiolane was obtained using a multienzymatic cascade protocol. By employing a combination of surfactant-treated subtilisin Carlsberg and Candida antarctica lipase B, the absolute configuration of the resulting 1,3-oxathiolane ring was efficiently controlled, resulting in an excellent enantiomeric excess (> 99%). This enantiopure 1,3-oxathiolane derivative is a key precursor to anti-HIV agents, such as lamivudine, through subsequent N-glycosylation.
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| 4. |
- Zhang, Peili, et al.
(författare)
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Paired Electrocatalytic Oxygenation and Hydrogenation of Organic Substrates with Water as the Oxygen and Hydrogen Source
- 2019
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Ingår i: Angewandte Chemie International Edition. - : Wiley-VCH Verlagsgesellschaft. - 1433-7851 .- 1521-3773. ; 58:27, s. 9155-9159
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Tidskriftsartikel (refereegranskat)abstract
- The use of water as an oxygen and hydrogen source for the paired oxygenation and hydrogenation of organic substrates to produce valuable chemicals is of utmost importance as a means of establishing green chemical syntheses. Inspired by the active Ni3+ intermediates involved in electro-catalytic water oxidation by nickel-based materials, we prepared NiBx as a catalyst and used water as the oxygen source for the oxygenation of various organic compounds. NiBx was further employed as both an anode and a cathode in a paired electrosynthesis cell for the respective oxygenation and hydrogenation of organic compounds, with water as both the oxygen and hydrogen source. Conversion efficiency and selectivity of >= 99% were observed during the oxygenation of 5-hydroxy-methylfurfural to 2,5-furandicarboxylic acid and the simultaneous hydrogenation of p-nitrophenol to p-aminophenol. This paired electrosynthesis cell has also been coupled to a solar cell as a stand-alone reactor in response to sunlight.
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