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排序方式: 共有589条查询结果,搜索用时 62 毫秒
1.
Kevin Grollier Alexis Taponard Clément Ghiazza Emmanuel Magnier Thierry Billard 《Helvetica chimica acta》2020,103(11):e2000185
α-Trifluoromethylselenolated enones constitute valuable building-blocks for further synthesis of innovative fluorinated compounds. Herein, we described an easy access to such compounds in green conditions through a Morita-Baylis-Hillman like reaction. These conditions have also been extended to higher fluorinated homologs. 相似文献
2.
Indermeet Kohli Taylor L. Braunberger Amanda F. Nahhas Fatima N. Mirza Mohsen Mokhtari Alexis B. Lyons Nikiforos Kollias Eduardo Ruvolo Henry W. Lim Iltefat H. Hamzavi 《Photochemistry and photobiology》2020,96(1):208-214
Human skin is exposed to visible light (VL; 400–700 nm) and long-wavelength ultraviolet A1 (UVA1) radiation (370–400 nm) after the application of organic broad-spectrum sunscreens. The biologic effects of these wavelengths have been demonstrated; however, a dose–response has not been investigated. Ten subjects with Fitzpatrick skin phototype IV-VI were enrolled. Subjects were irradiated with 2 light sources (80–480 J cm−2): one comprising VL with less than 0.5% UVA1 (VL+UVA1) and the other pure VL. Skin responses were evaluated for 2 weeks using clinical and spectroscopic assessments. 4-mm punch biopsies were obtained from nonirradiated skin and sites irradiated with 480 J cm−2 of VL+UVA1 and pure VL 24 h after irradiation. Clinical and spectroscopic assessments demonstrated a robust response at VL+UVA1 sites compared with pure VL. Histology findings demonstrated a statistically significant increase in the marker of inflammation (P < 0.05) and proliferation (P < 0.05) at the irradiated sites compared with nonirradiated control. Threshold doses of VL+UVA1 resulting in biologic responses were calculated. Results indicate that approximately 2 h of sun exposure, which equates to VL+UVA1 dose (~400 J cm−2), is capable of inducing inflammation, immediate erythema and delayed tanning. These findings reinforce the need of photoprotection beyond the UV range. 相似文献
3.
Marie-Ange Lespinasse Dr. Kaiyao Wei Justine Perrin Dr. Matthias Winkler Sieme Hamaidia Alexis Leroy Dr. Zuzana Macek Jilkova Dr. Christian Philouze Dr. Patrice N. Marche Dr. Carlo Petosa Dr. Jérôme Govin Dr. Anouk Emadali Dr. Yung-Sing Wong 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(64):e202202293
The pharmaceutical industry has a pervasive need for chiral specific molecules with optimal affinity for their biological targets. However, the mass production of such compounds is currently limited by conventional chemical routes, that are costly and have an environmental impact. Here, we propose an easy access to obtain new tetrahydroquinolines, a motif found in many bioactive compounds, that is rapid and cost effective. Starting from simple raw materials, the procedure uses a proline-catalyzed Mannich reaction followed by the addition of BF3 ⋅ OEt2, which generates a highly electrophilic aza-ortho-quinone methide intermediate capable of reacting with different nucleophiles to form the diversely functionalized tetrahydroquinoline. Moreover, this enantioselective one-pot process provides access for the first time to tetrahydroquinolines with a cis-2,3 and trans-3,4 configuration. As proof of concept, we demonstrate that a three-step reaction sequence, from simple and inexpensive starting compounds and catalysts, can generate a BD2-selective BET bromodomain inhibitor with anti-inflammatory effect. 相似文献
4.
One‐Pot Synthesis of O‐Allylhydroxylamines through the Organocatalytic Oxidation of Tertiary Allylic Amines Followed by a [2,3]‐Meisenheimer Rearrangement 下载免费PDF全文
Alexis Theodorou Dr. Dimitris Limnios Prof. Dr. Christoforos G. Kokotos 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(13):5238-5241
A cheap, green, and highly efficient one‐pot method for the synthesis of O‐protected allylic alcohols is described. By utilizing 2,2,2‐trifluoroacetophenone as the organocatalyst and H2O2 as the oxidant, a variety of allylic amine N‐oxides were synthesized, which upon heating are converted to the final products through a [2,3]‐Meisenheimer rearrangement. 相似文献
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Quantification of β‐aminopropionitrile,an inhibitor of lysyl oxidase activity,in plasma and tumor of mice by liquid chromatography tandem mass spectrometry 下载免费PDF全文
Christelle Machon Benjamin Le Calve Sylvie Coste Mirella Riviere Léa Payen David Bernard Jérôme Guitton 《Biomedical chromatography : BMC》2014,28(7):1017-1023
Lysyl oxidase enzymes are reported to be involved in patho‐physiological process such as tumorigenesis. β‐Aminopropionitrile (BAPN) is an irreversible inhibitor of lysyl oxidase activity, suggesting a potentially useful therapeutic of interest in oncology. This paper describes the first assay concerning the quantification of BAPN by mass spectrometry. A high‐performance liquid chromatography tandem mass spectrometry (LC‐MS/MS) assay was developed for the quantification of BAPN in plasma and tumor of mice. This method combines dansyl chloride (Dns) derivatization and extraction using a solid‐phase extraction Oasis© Max column. Deuterated BAPN was used as internal standard (IS). Separation was achieved using an C18 column HypersylGold, (ThermoElectron), 3.0 µm (100 × 2.1 mm i.d.). Gradient elution with water containing 0.1% acetic acid (A) and acetonitrile containing 0.1% acetic acid (B) was applied. Detection was performed with an electrospray ionization interface operating in negative ion mode. Selected reaction monitoring was used with ion transitions m/z 302 → 249 for BAPN–Dns and m/z 306 → 250 for the IS. The method was fully validated in plasma and was linear and sensitive in the range of 10–500 ng/mL. The lower limit of quantification in plasma was 2.5 ng/mL. This validated assay was successfully applied to a kinetic study of BAPN in mouse plasma and demonstrates that BAPN reaches the tumoral tissue. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
8.
Michèle?Thieullen Alexis?VigotEmail author 《Methodology and Computing in Applied Probability》2017,19(1):121-149
In this paper, we consider the composition of two independent processes: one process corresponds to position and the other one to time. Such processes will be called iterated processes. We first propose an algorithm based on the Euler scheme to simulate the trajectories of the corresponding iterated processes on a fixed time interval. This algorithm is natural and can be implemented easily. We show that it converges almost surely, uniformly in time, with a rate of convergence of order 1/4 and propose an estimation of the error. We then extend the well known Feynman-Kac formula which gives a probabilistic representation of partial differential equations (PDEs), to its higher order version using iterated processes. In particular we consider general position processes which are not necessarily Markovian or are indexed by the real line but real valued. We also weaken some assumptions from previous works. We show that intertwining diffusions are related to transformations of high order PDEs. Combining our numerical scheme with the Feynman-Kac formula, we simulate functionals of the trajectories and solutions to fourth order PDEs that are naturally associated to a general class of iterated processes. 相似文献
9.
Dr. Alexis Bordet Prof. Dr. Walter Leitner 《Angewandte Chemie (International ed. in English)》2023,62(33):e202301956
The rapidly growing importance of green hydrogen and renewable carbon resources as essential feedstocks for sustainable chemical value chains opens room for disruptive innovations regarding chemical production processes. The fluctuation and variability associated with non-fossil energy and raw material supply holds many challenges for catalysts to cope with the resulting dynamics. However, many new opportunities also arise once catalyst design starts to aim at performance that is “adaptive” rather than “task-specific”. In this Scientific Perspective, we propose to define adaptivity in catalysis on the basis of three essential properties that are reversibility, rapidity, and robustness (R3 rule). Promising design strategies and selected examples are described to substantiate the scientific concept and to highlight its potential for chemical energy conversion. 相似文献
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