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排序方式: 共有457条查询结果,搜索用时 15 毫秒
21.
The reaction of mercuric salts HgY2 or organic mercuric compounds RHHgX with long chain perfluorinated Grignard reagents RFMgBr leads to a series of new perfluoroalkyl mercury derivatives with the general formula RFHgZ (RF=C4F9, C6F13, C8F17 ; Z=RF,RH,Y with Y = I,Br,Cl, NO3,OCOCH3,OCOCF3).The synthesis of these organomercuric compounds is described, and their spectroscopic properties are reported. 相似文献
22.
23.
The sacrificial anode technique proved to be efficient for the selective and competitive silylation of 1-methylpyrrole bromides with trimethylchlorosilane and diorganodichlorosilanes. Linear and cyclic alternated 1-methyl-pyrrolylene-silanylene oligomers were obtained in good to high yields. 相似文献
24.
An efficient synthesis of diversely substituted N,N-dimethyl-4-oxo-2-(E)-alkenamides is reported. These derivatives were obtained in three steps from I,4benzodioxin with fair to good yields 相似文献
25.
26.
Bumhee Lim Yangyang Cheng Takehiro Kato Anh-Tuan Pham Eliott Le Du Abhaya Kumar Mishra Elija Grinhagena Dimitri Moreau Naomi Sakai Jerome Waser Stefan Matile 《Helvetica chimica acta》2021,104(8):e2100085
Thiol-mediated uptake is emerging as method of choice to penetrate cells. This study focuses on irreversible covalent inhibitors of thiol-mediated uptake. High-content high-throughput screening of the so far largest collection of hypervalent iodine reagents affords inhibitors that are more than 250 times more active than Ellman’s reagent and rival the best dynamic covalent inhibitors. Comparison with other irreversible reagents reveals that inhibition within one series follows reactivity, whereas inhibition across series deviates from reactivity. These trends support that molecular recognition, besides dynamic covalent exchange, contributes significantly to thiol-mediated uptake. The most powerful inhibitors besides the best hypervalent iodine reagents were Fukuyama’s nosyl protecting group and super-cinnamaldehydes that have been introduced as irreversible activators of the pain receptor TRPA1. Considering that several viruses use different forms of thiol-mediated uptake to enter cells, the identification of new irreversible inhibitors of thiol-mediated uptake is of general interest for the discovery of new antivirals. 相似文献
27.
A general feature of the cationic polymerization of all cyclodimethylsiloxanes is the formation of various cyclic products (cyclics) together with that of a linear high polymer. However, the types of cyclics as well as their rate of formation may vary considerably according to the number x of D units ((CH3)2SiO units) in the monomer. The case of initiation by trifluoromethanesulfonic (triflic) acid in methylene chloride solution at 20°C has been particularly studied. With D4, D5, D6 and D7, for which the polymerization rate increases with the size of the ring, all types of cycles Dx are formed in relative amount decreasing with their size ([D7] < [D6] < [D5] < [D4]). The high polymer final concentration and molecular weight are independent from triflic acid concentration. This may result from a polymerization-depolymerization reaction, involving all the cyclics formed by back-biting reactions occurring with silyl triflates activated by the acid, and leading finally to an equilibrium. The situation with D3 is completely different. The high polymer (HP) and the cyclics (D3x multiples of D3 like D6, D9, …) are formed simultaneously under kinetic control. The yields of the various cyclics (formed in amount often larger than that of the HP) are proportional to that of the linear HP. The latter is formed from the beginning of the reaction with a molecular weight proportional to HP yield and inversely proportional to the acid concentration. The opposite role of added water on the polymerization is discussed: an activating effect for D3, and a desactivating one for D4, D5 and D6. “Copolymerization” experiments between D3 (or D4) and tetramethyldisiloxane diol confirmed the effect of water and gave new informations about the occurrence - or absence - of condensation reactions in the mechanism of the growth of the polymer chains. A discussion leads to the conclusion that while the cationic polymerization of D4 by triflic acid is propagated by activated triflic esters, that of D3 may also involve the monomer activated by the higher hydrates of the acid and linear oligomeric silanol esters. The latter, formed continuously, may also give the D3x cyclics by intramolecular heterocondensation. 相似文献
28.
Jacqueline Destain Patrick Fickers Frédéric Weekers Benoît Moreau Philippe Thonart 《Applied biochemistry and biotechnology》2005,121(1-3):269-277
In this article, we report the development and optimization of an industrial culture medium for the production of extracellular
lipase in the yeast Yarrowia lipolytica. Until now olive oil in combination with glucose was used as the carbon source and inducer for the production of lipase.
Our results demonstrate that methyloleate, a cheap hydrophobic compound, could efficiently substitute olive oil as the inducer
and carbon source for lipase production. A new process of lipase production was developed yielding a twofold increase in the
level of production compared with the levels in previous reports. 相似文献
29.
Krief A Destree A Durisotti V Moreau N Smal C Colaux-Castillo C 《Chemical communications (Cambridge, England)》2002,(6):558-559
Driving the equilibrium between selenides and osmium(VIII) reagents with selenoxides and osmium(VI) by a subsequent reaction (rearrangement of allyl selenoxides to allyl alcohols or addition of osmium(VIII) species on C=C double bonds) to one side, allows the transformation of methyl geranyl selenides to linalool and of methyl citronellyl selenoxide to 6,7-dihydroxy citronellyl selenide. 相似文献
30.
Jacques Marie Moreau Gérard Delbos André Marie Bottreau 《Journal of Molecular Liquids》1983,25(2):91-101
The dielectric studies of four components mixtures are rarely made on a great deal of concentrations. The authors propose a dielectric behavior study of mixtures made with toluene-water-butanol-SDS, from specific mappings of permittivities which are plotted on pseudo ternary diagrams at 9.455 GHz. They draw different conclusions to know how at 9.455 GHz the variations of real and imaginary parts of permittivity involve the concentration of each component and the structure of the mixture.These conclusions will be perfected by studies made at other frequencies and by spectral analysis of each mixture. 相似文献