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Axundova F. N. Kurbanova M. M. Huseynzada A. E. Alves M. J. 《Russian Journal of Organic Chemistry》2019,55(12):1975-1978
(S)-(1,2,3,6-Tetrahydropyridazin-3-yl)methanol was synthesized in two steps by the Diels-Alder reaction of penta-2,4-dien-1-ol with diethyl azodicarboxylate in the presence of (S)-BINOL as chiral catalyst. The subsequent Boc-protection of the 2-position of the pyridazine ring, ring-closing carbonylation of the hydroxy group, and deprotection afforded a bicyclic iminosugar analog. The structure of the isolated compounds was proved by NMR, IR, and mass spectra and elemental analyses.
相似文献3.
Tiago Augusto Donegatti Alnilan Lobato Luís Moreira Gonalves Elisabete Alves Pereira 《Electrophoresis》2019,40(22):2929-2935
Aldehydes are important compounds in a large number of samples, especially food and beverages. In this work, for the first time, cyclohexane‐1,3‐dione (CHD) was used as a derivatizing reagent aiming aldehyde (formaldehyde, acetaldehyde, propionaldehyde, and valeraldehyde) analysis by MEKC‐DAD. The optimized separation of the derivates was performed using a voltage program (+20 kV, 0–15 min.; +23 kV, 15–17 min.) at a temperature of 26°C, and using as the running buffer a mixture containing 100 mmol/L of sodium dodecyl sulfate and 29 mmol/L of sodium tetraborate at pH 9.2, with maximum absorbance at 260 nm. CHD was compared with two other derivatizing agents: 3‐methyl‐2‐benzothiazolinone hydrazone and phenylhydrazine‐4‐sulfonic acid. The CHD‐aldehyde derivatives were also characterized by LC‐MS. The calibration curves for all aldehydes had r2 above 0.999 and LODs ranged from 0.01 to 0.7 mg/L. The optimized methodology was applied in sugar cane brandy (cachaça) samples successfully. CHD showed to be an alternative derivatization reagent due to its stability, aqueous solubility, high selectivity and sensitivity, reduced impurities, and simple preparation steps. 相似文献
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Carbon Dots (C‐dots) from Cow Manure with Impressive Subcellular Selectivity Tuned by Simple Chemical Modification 下载免费PDF全文
Cintya D'Angelis do E. S. Barbosa Dr. José R. Corrêa Gisele A. Medeiros Gabrielle Barreto Dr. Kelly G. Magalhães Dr. Aline L. de Oliveira Prof. Dr. John Spencer Prof. Dr. Marcelo O. Rodrigues Prof. Dr. Brenno A. D. Neto 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(13):5055-5060
Improved cellular selectivity for nucleoli staining was achieved by simple chemical modification of carbon dots (C‐dots) synthesized from waste carbon sources such as cow manure (or from glucose). The C‐dots were characterized and functionalized (amine‐passivated) with ethylenediamine, affording amide bonds that resulted in bright green fluorescence. The new modified C‐dots were successfully applied as selective live‐cell fluorescence imaging probes with impressive subcellular selectivity and the ability to selectively stain nucleoli in breast cancer cell lineages (MCF‐7). The C‐dots were also tested in four other cellular models and showed the same cellular selection in live‐cell imaging experiments. 相似文献
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Ultrasound treatment favors enzymatic attack on vegetal materials and influences biological activity. The objective of this study was to develop substrates for Saccharomyces cerevisiae based on the hydrothermal treatment and ultrasound treatment of pine needle biomass. The samples subjected to ultrasound treatment at 550?°C and 650?°C showed higher reflectance bands at around 200?nm after 80?min of ultrasound treatment and lower band gap energies associated with lower IC30 values. The hydrothermal treatment with 100?min of ultrasound treatment generated more promising materials for the use of the substrates with the eukaryotic model S. cerevisiae. 相似文献
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Ana Diniz Dr. Helena Coelho Dr. Jorge S. Dias Dr. Sandra J. van Vliet Prof. Dr. Jesús Jiménez-Barbero Prof. Dr. Francisco Corzana Prof. Dr. Eurico J. Cabrita Dr. Filipa Marcelo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(61):13945-13955
The human macrophage galactose-type lectin (MGL), expressed on macrophages and dendritic cells (DCs), modulates distinct immune cell responses by recognizing N-acetylgalactosamine (GalNAc) containing structures present on pathogens, self-glycoproteins, and tumor cells. Herein, NMR spectroscopy and molecular dynamics (MD) simulations were used to investigate the structural preferences of MGL against different GalNAc-containing structures derived from the blood group A antigen, the Forssman antigen, and the GM2 glycolipid. NMR spectroscopic analysis of the MGL carbohydrate recognition domain (MGL-CRD, C181-H316) in the absence and presence of methyl α-GalNAc (α-MeGalNAc), a simple monosaccharide, shows that the MGL-CRD is highly dynamic and its structure is strongly altered upon ligand binding. This plasticity of the MGL-CRD structure explains the ability of MGL to accommodate different GalNAc-containing molecules. However, key differences are observed in the recognition process depending on whether the GalNAc is part of the blood group A antigen, the Forssman antigen, or GM2-derived structures. These results are in accordance with molecular dynamics simulations that suggest the existence of a distinct MGL binding mechanism depending on the context of GalNAc moiety presentation. These results afford new perspectives for the rational design of GalNAc modifications that fine tune MGL immune responses in distinct biological contexts, especially in malignancy. 相似文献
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Osorio Ana C. P. de Sena Rodrigo C. Araújo Thiago de O. de Almeida Marcelo D. 《Accreditation and quality assurance》2019,24(5):387-394
Accreditation and Quality Assurance - The production of Certified Reference Materials (CRMs) is one of the essential activities of the National Institute of Metrology, Quality and Technology... 相似文献
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