Vacuum ultraviolet photoionization of a gas-phase oligonucleotide anion leads to the formation of a valence hole. This hole migrates towards an energetically favorable site where it can weaken bonds and ultimately lead to bond cleavage. We have studied Vacuum UV photoionization of deprotonated oligonucleotides containing the human telomere sequence dTTAGGG and G-quadruplex structures consisting of four dTGGGGT single strands, stabilized by NH counter ions. The oligonucleotide and G-quadruplex anions were confined in a radiofrequency ion trap, interfaced with a synchrotron beamline and the photofragmentation was studied using time-of-flight mass spectrometry. Oligonucleotide 12-mers containing the 5'-TTAGGG sequence were found to predominantly break in the GGG region, whereas no selective bond cleavage region was observed for the reversed 5'-GGGATT sequence. For G-quadruplex structures, fragmentation was quenched and mostly non-dissociative single and double electron removal was observed.
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http://dx.doi.org/10.1002/chem.201904105 | DOI Listing |
J Environ Manage
January 2025
Changzhou Key Laboratory of Biomass Green, Safe and High Value Utilization Technology, Institute of Urban and Rural Mining, Changzhou University, No.21 Gehu Road, Wujin District, Changzhou, 213164, China; National-Local Joint Engineering Research Center for Biomass Refining and High-Quality Utilization, Changzhou University, No.21 Gehu Road, Wujin District, Changzhou, 213164, China. Electronic address:
Erythromycin is becoming one of the most common contaminants detected in surface water and wastewater, which poses a potential risk to ecological systems and human health. Until now, there is still no effective way to eliminate it. Herein, a novel and efficient erythromycin-degrading fungus Peniophora incarnata F1, capable of utilizing erythromycin as its sole source of carbon and energy, was isolated from contaminated sludge.
View Article and Find Full Text PDFMolecules
January 2025
School of Environment and Public Health, Xiamen Huaxia University, Xiamen 361024, China.
In this study, we present the HOAc-catalyzed selective cleavage of the C=C double bond of enaminones, enabling the formation of a new C-N bond and a new C=N bond for the one-pot synthesis of 2-substituted 3,4-dihydroquinazolines directly from ynones and 2-(aminomethyl)anilines. This method operates in ethanol under transition-metal-free and oxidant-free conditions, offering a sustainable and efficient approach for the synthesis of 3,4-dihydroquinazolines with broad functional group tolerance.
View Article and Find Full Text PDFNat Mater
January 2025
Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA.
Van der Waals materials display rich structural polymorphs with distinct physical properties. An atomistic understanding of the phase-transition dynamics, propagation pathway and associated evolution of physical properties is essential for capturing their potential in practical technologies. However, direct visualization of the rapid phase-transition process is fundamentally challenging due to the inherent trade-offs among atomic resolution, field of view and imaging frame rate.
View Article and Find Full Text PDFNat Commun
January 2025
School of Materials Science and Chemical Engineering, Institute of Drug Discovery Technology, Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo, PR China.
C-C bond cleavage and recombination provide an efficient strategy for the modification and reconstruction of molecule structures. Herein, we present a method for achieving amidation of aryl C(sp)-H bond through the cleavage and recombination of C-C triple bond with the involvement of nitrous acid esters. This method marks the instance of precise and controlled stepwise cleavage of C-C triple bond, offering a fresh perspective for the cleavage of such bonds.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Anhui Normal University, School of Chemistry and Materials Science, 189 Jiuhua South Road, 241002, Wuhu, CHINA.
Achieving axially chiral biaryl dialdehydes through asymmetric catalysis remains significantly challenging due to the lack of efficient strategies. In this report, we developed a rhodium-catalyzed enantioselective C-H amidation through chiral transient directing group strategy. With this new approach, a series of axially chiral amido dialdehydes were achieved in up to 86% yields with 99.
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