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排序方式: 共有408条查询结果,搜索用时 15 毫秒
1.
2.
Robert WeavingEmmanuel Roulland Claude MonneretJean-Claude Florent 《Tetrahedron letters》2003,44(12):2579-2581
A synthesis of the alkylidene cyclopentenone prostaglandin TEI 9826 has been realized. The synthesis involved the preparation of the chiral 1,5-diene 8 using a stereoselective Claisen rearrangement from the allylic alcohol 6 giving the ester 7 after vinylation. Then a key RCM reaction allowed the preparation of the cyclopentenol 9 which, after oxidation, gave the cyclopentenone 10, precursor of the prostaglandin. 相似文献
3.
4.
An experimental investigation of the frequency response of electrochemical probes to transversal velocity fluctuation is reported. The study has been focused on wall shear stress for a modulated flow due to an oscillating cylinder along its own axes since the wall shear stress has been first numerically determined for this flow. Results indicate that a frequency response correction to probe outputs is required and that this correction depends on the amplitude of fluctuations.List of symbols
A
total area of the electrode
-
A
i
area of the part i of the electrode
-
a
amplitude of oscillation
-
C
concentration
-
c
fluctuation of concentration
-
D
cylinder diameter
-
D
diffusion coefficient
-
h
dimensionless velocity normal to the wall
-
H
transfer function modulus
-
K
i
transfer coefficient
-
l
electrode length
-
n
frequency
-
S
wall shear
-
S
fluctuation of the wall shear
-
U
mean value of the fluid velocity far from the wall
-
u
streamwise component of the fluid velocity
-
spanwise component of the fluid velocity (along the cylinder axis)
-
w
component of the fluid velocity perpendicular to the wall
-
x
direction of the mean flow
-
y
direction parallel to the cylinder axis
-
z
direction perpendicular to the wall
-
v
kinematic viscosity
-
dimensionless distance perpendicular to the wall (z)
-
dimensionless distance (x)
-
phase shift
-
azimuthal angle
-
modulation frequency 相似文献
5.
Quentin Ronzon Dr. Wei Zhang Dr. Nicolas Casaretto Dr. Elisabeth Mouray Prof. Dr. Isabelle Florent Dr. Bastien Nay 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(28):7764-7772
The introduction of substituents on bare heterocyclic scaffolds can selectively be achieved by directed C−H functionalization. However, such methods have only occasionally been used, in an iterative manner, to decorate various positions of a medicinal scaffold to build chemical libraries. We herein report the multiple, site selective, metal-catalyzed C−H functionalization of a “programmed” 4-hydroxyquinoline. This medicinally privileged template indeed possesses multiple reactive sites for diversity-oriented functionalization, of which four were targeted. The C-2 and C-8 decorations were directed by an N-oxide, before taking benefit of an O-carbamoyl protection at C-4 to perform a Fries rearrangement and install a carboxamide at C-3. This also released the carbonyl group of 4-quinolones, the ultimate directing group to functionalize position 5. Our study highlights the power of multiple C−H functionalization to generate diversity in a biologically relevant library, after showing its strong antimalarial potential. 相似文献
6.
Access to New Endoperoxide Derivatives by Electrochemical Oxidation of Substituted 3‐Azabicyclo[4.1.0]hept‐4‐enes 下载免费PDF全文
Dr. Frédérick Nuter Dr. Abdou Khadre Djily Dimé Dr. Cheng Chen Dr. Lotfi Bounaadja Dr. Elisabeth Mouray Dr. Isabelle Florent Dr. Yvan Six Dr. Olivier Buriez Dr. Angela Marinetti Dr. Arnaud Voituriez 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5584-5593
A series of substituted 3‐azabicyclo[4.1.0]hept‐4‐ene derivatives were prepared and analysed by cyclic voltammetry. Preparative aerobic electrochemical oxidation reactions were then carried out. Three original endoperoxides were isolated, characterised and subjected to antimalarial and cytotoxicity activity assays. 相似文献
7.
Florent Jasinski Emeline Lobry Lénaïg Lefevre Abraham Chemtob Céline Croutxe‐Barghorn Xavier Allonas Adrien Criqui 《Journal of polymer science. Part A, Polymer chemistry》2014,52(13):1843-1853
The use of UV light to initiate emulsion polymerization processes is generally overlooked, whilst extensive literature exists on photocuring of monomer films. In this study, the unique potential of UV light to produce at ambient temperature polyacrylate latexes without initiator was exploited. Although radical initiators are utilized at low concentration, their cost, toxicity, and odor provide incentives for finding alternatives. Starting with concentrated (30 wt %) and low scattering acrylate miniemulsions (droplet diameter <100 nm), it was demonstrated that acrylate self‐initiation can promote an efficient and fast photopolymerization in micrometer‐scale reactor (spectrophotometric cell) and lab‐scale photoreactor. Herein, all kinetic, colloidal, and mechanistic aspects involved in the self‐initiation of acrylate miniemulsion were extensively examined to provide a complete picture. In particular, the effects of droplet size, initiating wavelength, optical path, and irradiance on the course of the polymerization were thoroughly discussed. A diradical self‐initiation pathway is the most likely mechanism. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1843–1853 相似文献
8.
Formation of homogeneous nanocomposite films at ambient temperature via miniemulsion polymerization using graphene oxide as surfactant 下载免费PDF全文
Yasemin Fadil S. H. C. Man Florent Jasinski Hideto Minami Stuart C. Thickett Per B. Zetterlund 《Journal of polymer science. Part A, Polymer chemistry》2017,55(14):2289-2297
A convenient and industrially scalable method for synthesis of homogeneous nanocomposite films comprising poly(styrene‐stat‐butyl acrylate) and nanodimensional graphene oxide (GO) or reduced GO (rGO) is presented. Importantly, the nanocomposite latex undergoes film formation at ambient temperature, thus alleviating any need for high temperature or high pressure methods such as compression molding. The method entails synthesis of an aqueous nanocomposite latex via miniemulsion copolymerization relying on nanodimensional GO sheets as sole surfactant, followed by ambient temperature film formation resulting in homogeneous film. For comparison, a similar latex obtained by physical mixing of a polymer latex with an aqueous GO dispersion results in severe phase separation, illustrating that the miniemulsion approach using GO as surfactant is key to obtaining homogeneous nanocomposite films. Finally, it is demonstrated that the GO sheets can be readily reduced to rGO in situ by heat treatment of the film. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2289–2297 相似文献
9.
Majdi Mabrouk Mickael Marchand Jean-Marie Baronnet Florent Lemont 《Plasma Chemistry and Plasma Processing》2016,36(4):1085-1110
This work deals with incineration of organic liquid wastes using an oxygen thermal plasma jet, submerged in water. The results presented here concern incineration of trichloroethylene (TCE). During a trial run, the CO2 and CO content in the exhaust gas is continuously measured; samples taken periodically from the solution are analyzed by appropriate methods: total organic carbon and chlorine content are measured. Process efficiency during tests with a few L/h of TCE is given by the mineralization rate. The trapping rate of chlorine as HCl is near 100 %. The TCE destruction and removal efficiency, measured by MS/GC, is better than 99.9999 %. A simplified kinetic model of gas quenching was constructed from a single-phase plug-flow reactor model taking into account 14 species and 34 reactions. It satisfies the requirements of heat balance and major components analysis, and reveals the major role of the OH radical on the concentrations of CO as well as HCl and/or Cl2 in the off-gas stream. 相似文献