Bioorthogonal labeling reveals different expression of glycans in mouse hippocampal neuron cultures during their development

The following are available online. Scheme S1: Synthesis of peracetylated azidomannose (Ac4ManNAz); Scheme S2: Alternative synthesis of GlcNAz using chloroacetic anhydride and NaOH as a base; Scheme S3: Synthesis of peracetylated azidofucose (Ac4FucAz); Figure S1: 1H-NMR spectra of ManNAz (D2O, 300 MHz); Figure S2: 1H-NMR spectra of Ac4ManNAz (CDCl3 , 300 MHz), mixture of anomers; Figure S3: HPLC chromatogram of purified Ac4ManNAz showing the two anomers; Figure S4: 1H-NMR spectra of GlcNAz (D2O, 300MHz); Figure S5: 1H-NMR spectra of Ac4GlcNAz (CDCl3 , 300 MHz), mixture of anomers; Figure S6: HPLC chromatogram of purified Ac4GlcNAz showing the two anomers; Figure S7: 1H-NMR spectra of 6-azido-1,2,3,4-tetra-O-acetyl-6-deoxy-α,β-L-galactopyranose Ac4FucAz (CDCl3 , 300 MHz): mixture of anomers; Table S1: Primer sequences used in qRT-PCR.The expression of different glycans at the cell surface dictates cell interactions with their environment and other cells, being crucial for the cell fate. The development of the central nervous system is associated with tremendous changes in the cell glycome that is tightly regulated. Herein, we have employed biorthogonal Cu-free click chemistry to image temporal distribution of different glycans in live mouse hippocampal neurons during their maturation in vitro. We show development-dependent glycan patterns with increased fucose and decreased mannose expression at the end of the maturation process. We also demonstrate that this approach is biocompatible and does not affect glycan transport although it relies on an administration of modified glycans. The applicability of this strategy to tissue sections unlocks new opportunities to study the glycan dynamics under more complex physiological conditions.This research was funded by the European Union Framework Programme for Research and Innovation Horizon 2020 under grant agreement n.º 668983—FoReCaST, by European Union’s Horizon 2020 Research and Innovation programme, under the Grant Agreement number 739572–The Discoveries CTR, and the project NORTE-01-0145-FEDER-000023, supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER)

Efficient Synthesis of Fluorescent Coumarins and Phosphorous-Containing Coumarin-Type Heterocycles via Palladium Catalyzed Cross-Coupling Reactions

Quantum-chemical calculations on the spectral properties of some aryl substituted 3- phosphonocoumarins were performed, and the effect of the substituents in the aryl moiety was evaluated. The structures possessing promising fluorescent properties were successfully synthesized via Suzuki and Sonogashira cross-coupling. The synthetic protocol was also applied for the phosphorous chemoisomer of 3-phosphonocoumarin, 1,2-benzoxaphosphorin, and their carboxylate analogues. The optical properties of the arylated and alkynylated products were experimentally determined. The obtained quantum-chemical and experimental results give the possibility for a fine tuning of the optical properties of phosphorous-containing coumarin systems by altering the substituent at its C-6 position

Theoretical and Experimental Local Reactivity Parameters of3‑Substituted Coumarin Derivatives

International audienceLocal reactivity descriptors, such as atomic charges, atomic electrostatic potential andatomic Fukui indices were computed for a series of 3-substituted coumarin (2-oxo-2H-1-benzopyran)derivatives, using density functional theory (DFT) and Möller−Plesset methods (MP2). The variationof those properties as a function of the substituents was compared with the variation of the measuredXPS binding energies. The atomic electrostatic potentials and XPS binding energies serves as indicatorsof the electrophilicity of a given center within a molecule, while the atomic Fukui indices describe itsdegree of electronic localization, known as atomic softness. The correlation between those theoreticaland experimental properties allowed us to follow the effect of electron withdrawing substituents on theelectrophilicity of a given atomic center. The Fukui indices provided additional information about thesoftening/hardening of the center of interest due to presence of different substituents to the coumarin system. On the basis ofthese analysis, the 1,2-addition would be favored for 3-acetyl, 3-phosphono, and 7-diethylamino substituents, while 3-carboxyl, 3-ethoxycarbonyl, and 3-nitro substituent would favor 1,4-addition. The substituted coumarins would preferably react with softnucleophiles at position 2 and with hard nucleophiles at position 4

A New and Efficient Method for the Synthesis of 3,4-Disubstituted Pyrrolidine-2,5-diones

A newly found reaction for the synthesis of 3,4-disubstituted 1-hydroxy-pyrrolidine-2,5-diones from 3-substituted coumarins and nitromethane has been elaborated. The reaction involved a simple and convenient experimental procedure. The applicability of the rearrangement reaction is determined

Abstracts Of The Proceedings And The Posters From The Third Scientific Session Of The Medical College Of Varna

October 2-3, 201