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排序方式: 共有92条查询结果,搜索用时 62 毫秒
81.
Dr. Christopher D. Reinkemeier Christine Koehler Dr. Paul F. Sauter Dr. Nataliia V. Shymanska Dr. Cecile Echalier Dr. Anna Rutkowska Dr. David W. Will Prof. Dr. Carsten Schultz Prof. Dr. Edward A. Lemke 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(19):6094-6099
Bioorthogonal reactions are ideally suited to selectively modify proteins in complex environments, even in vivo. Kinetics and product stability of these reactions are crucial parameters to evaluate their usefulness for specific applications. Strain promoted inverse electron demand Diels–Alder cycloadditions (SPIEDAC) between tetrazines and strained alkenes or alkynes are particularly popular, as they allow ultrafast labeling inside cells. In combination with genetic code expansion (GCE)-a method that allows to incorporate noncanonical amino acids (ncAAs) site-specifically into proteins in vivo. These reactions enable residue-specific fluorophore attachment to proteins in living mammalian cells. Several SPIEDAC capable ncAAs have been presented and studied under diverse conditions, revealing different instabilities ranging from educt decomposition to product loss due to β-elimination. To identify which compounds yield the best labeling inside living mammalian cells has frequently been difficult. In this study we present a) the synthesis of four new SPIEDAC reactive ncAAs that cannot undergo β-elimination and b) a fluorescence flow cytometry based FRET-assay to measure reaction kinetics inside living cells. Our results, which at first sight can be seen conflicting with some other studies, capture GCE-specific experimental conditions, such as long-term exposure of the ring-strained ncAA to living cells, that are not taken into account in other assays. 相似文献
82.
Chen AM Ellison ME Peresypkin A Wenslow RM Variankaval N Savarin CG Natishan TK Mathre DJ Dormer PG Euler DH Ball RG Ye Z Wang Y Santos I 《Chemical communications (Cambridge, England)》2007,(4):419-421
We report the first case of a pharmaceutical cocrystal formed between an inorganic acid and an active pharmaceutical ingredient (API), which enabled us to develop a stable crystalline and bioavailable solid dosage form for pharmaceutical development where otherwise only unstable amorphous free form or salts could have been used. 相似文献
83.
Festa C De Marino S Sepe V D'Auria MV Bifulco G Débitus C Bucci M Vellecco V Zampella A 《Organic letters》2011,13(6):1532-1535
Two unprecedented cyclic peptides, solomonamides A and B, were isolated from the marine sponge Theonella swinhoei. The structures were elucidated on the basis of comprehensive 1D and 2D NMR analysis and high-resolution mass spectrometry. A combined approach, involving Marfey's method, QM J based analysis, and DFT J/(13)C calculations, was used for establishing the absolute configuration of the entire molecule. Solomonamide A showed in vivo anti-inflammatory activity. 相似文献
84.
Oscar Moradei Cecile du Mortier Alicia Fernández Cirelli Joachim Thiem 《Journal of carbohydrate chemistry》2013,32(4-5):525-532
Abstract The stereospecific synthesis of methyl 3-O-benzoyl-6-O-(tert-butyldiphenylsilyl)-2-deoxy-α-d-erythro-hexopyranosid-4-ulose (5) - a Thromboxane B2 (TXB2) precursor -starting from D-galactose is described. Facile and established methods including selective benzoylation, oxidation-elimination and a stereocontrolled hydrogenation (Pd/charcoal) were employed effectively. 相似文献
85.
The adsorption isotherms of phenol, caffeine, propranolol chloride, and amitriptyline chloride were measured on three new brands of C(18)-bonded silica that have been designed to be more resistant than conventional C18-bonded silica at high pHs (>8). These columns were the 4 microm Bidendate Cogent-C18 (Microsolv Technology Corporation, Long Branch, NJ, USA), the 3.5 microm Zorbax Extend-C18 (Agilent Technologies, Palo Alto, CA, USA), and the 5 microm XTerra-C18 (Waters, Milford, MA, USA). The originality of these adsorbents is due to their surface chemistry, which protects them from rapid hydrolysis or dissolution at extreme pH conditions. Their adsorption properties were compared to those of the 3 microm Luna-C18 (Phenomenex, Torrance, CA), which is a more conventional monofunctional material. The adsorption data were acquired by frontal analysis (FA) and the adsorption energy distributions (AEDs) of all systems studied were calculated by the expectation-maximization (EM) method. The experimental results show that neither a simple surface protection (Extend-C18) nor the elimination of most of the silanol groups (Cogent-C18) is sufficient to avoid a peak tailing of the basic compounds at pH 8 that is of thermodynamic origin. The incorporation of organic moieties in the silica matrix, which was achieved in XTerra-C18, the first generation of hybrid methyl/silica material, reduces the silanols activity and is more successful in reducing this peak tailing. 相似文献
86.
Guerrero-Sanchez C Gohy JF D'Haese C Thijs H Hoogenboom R Schubert US 《Chemical communications (Cambridge, England)》2008,(24):2753-2755
Poly(2-nonyl-2-oxazoline-block-2-ethyl-2-oxazoline) block copolymer micelles were investigated as an alternative system to the approach proposed by He and Lodge (Y. He and T. P. Lodge, J. Am. Chem. Soc., 2006, 128, 12666) for the thermoreversible transfer of micelles between a hydrophobic ionic liquid phase and an aqueous phase; this work describes the possibility of thermally triggering and controlling this process. 相似文献
87.
A one-step, surfactant-assisted, seed-mediated method has been utilized for the growth of short gold nanorods with reasonable yield by modifying an established synthesis protocol. Among the various parameters that influence nanorod growth, the impact of the bromide counterion has been closely scrutinized. During this study it has been shown that, irrespective of its origin, the bromide counterion [cetyltrimethylammonium bromide (CTAB) or NaBr] plays a crucial role in the formation of nanorods in the sense that there is a critical [Br(-)]/[Au(3+)] ratio (around 200) to achieve nanorods with a maximum aspect ratio. Beyond this value, bromide can be considered as a poisoning agent unless shorter nanorods are required. The use of AgNO(3) helps in symmetry breaking for gold nanorod growth, whereas the bromide counterion controls the growth kinetics by selective adsorption on the facets of the growth direction. Thus, a proper balance between bromide ions and gold cations is also one of the necessary parameters for controlling the size of the gold nanorods; this has been discussed thoroughly. The results have been discussed based on their absorption spectra and finally shape evolution has been confirmed by TEM. Due to their efficient absorption in the near-IR region, these short nanorods were used in photothermal imaging of living COS-7 cells with improved signal-to-background ratios. 相似文献
88.
Subramaniam AB Mejean C Abkarian M Stone HA 《Langmuir : the ACS journal of surfaces and colloids》2006,22(14):5986-5990
We report the behavior of particle-stabilized bubbles (armored bubbles) when exposed to various classes and concentrations of surfactants. The bubbles are nonspherical, which is a signature of the jamming of the particles on the interface, and are stable to dissolution prior to the addition of surfactant. Armored bubbles exposed to surfactants, dissolve, and exhibit distinct morphological, microstructural, and lifetime changes, which correlate with the concentration of surfactant employed. For low concentrations of surfactant, an armored bubble remains nonspherical while dissolving, whereas for concentrations close to and above the surfactant cmc a bubble reverts to a spherical shape before dissolving. We propose a microstructural interpretation, supported by our experimental observations of particle dynamics on the bubble interface, that recognizes the role of interfacial jamming and stresses in particle-stabilization and surfactant-mediated destabilization of armored bubbles. 相似文献
89.
[reaction: see text] The reaction of a variety of indoles with N-thioalkyl- and N-thioarylphthalimides to produce 3-thioindoles is reported. Catalytic quantities of halide-containing salts are crucial to the success of this reaction. This highly efficient reaction provides sulfenylated indoles from bench-stable, readily available starting materials in good to excellent yields. 相似文献
90.