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1.
G. Mouysset G. Grassy M. Payard G. Commenges A. Carpy J. Couquelet 《Journal of heterocyclic chemistry》1988,25(4):1167-1171
When diazomethane was reacted with 2-cyano chromones, three isomeric N-methyltriazoles were obtained. They were isolated by liquid chromatography with three different solvents for elution. Complete elucidation of the structures was performed both by pmr and cmr spectrography; X-ray analysis is in agreement with the proposed structures. 相似文献
2.
The synthesis fo 3-amino- and 3-hydroxy-2-methyl-4,4-spiro-cyclohexane-2-butene-4-olide was achieved starting from isocyanate or an isocyanate precursor. The study and discussion of tautomeric structures were peformed using ir and nmr spectra functional groups reactivity. 相似文献
3.
Legendre B. Baziard-Mouysset G. Anastassiadou M. Leger J. M. Payard M. 《Journal of Thermal Analysis and Calorimetry》2001,66(2):659-673
The compound 2-(2-benzofuryl) Δ-2 imidazoline, has been studied by DSC, TG, X-ray diffraction and thermomicroscopy.
We shall see that in the case of a study by DSC this compound presents a strange behaviour, which apparently is in contradiction
with the thermodynamic rules. In a case of monotropy, if we have the α-phase (stable) and the γ-phase (metastable), after
melting and cooling only theα-phase could crystallise. But this compound can give, according to the rate of cooling, theγ-phase
metastable. The rate of cooling is of fundamental importance and the monotropic behaviour of this compound will be explained
using the Gibbs function G=f(T) for P=1 atm.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
4.
Pascale Besse Genevive Baziard-Mouysset Kamal Boubekeur Pierre Palvadeau Henri Veschambre Marc Payard Guy Mousset 《Tetrahedron: Asymmetry》1999,10(24):199-4754
From the microbiological reductions of 2-acetyl or 2-benzoylchromen-4-one both enantiomers of the corresponding alcohols were obtained with high enantiomeric excess. The absolute configurations were determined directly by an X-ray structural determination. The results obtained showed that for most of the microorganisms tested, an inversion of the configuration of the alcohol occurred with the change of the substituent (methyl to phenyl group) in position 2, but also with the presence of a bromine atom in position 6 of the aromatic ring, positioned quite far from the prochiral centre. 相似文献
5.
Ming-Yu Chen Sylvain Charvet Dr. Pierre-Adrien Payard Dr. Marie-Eve L. Perrin Dr. Julien C. Vantourout 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(2):e202311165
A robust electrochemically driven nickel-catalyzed halogen exchange of unsaturated halides and triflates (Br to Cl, I to Cl, I to Br, and OTf to Cl) is reported. A combination of NiCl2 ⋅ glyme as the precatalyst, 2,2′-bipyridine as a ligand, NMP as the solvent, and electrochemistry allowed the generation of a nickel species that promotes reductive elimination of the desired product. This paired electrochemical halogenation is compatible with a range of unsaturated halides and triflates, including heterocycles, dihaloarenes, and alkenes with good functional-group tolerance. Joint experimental and theoretical mechanistic investigations highlighted three catalytic events: i) oxidative addition of the aryl halide to a Ni(0) species to deliver a Ni(II) intermediate; ii) halide metathesis at Ni(II); iii) electrochemical oxidation of Ni(II) to Ni(III) to enable the formation of the desired aryl halide upon reductive elimination. This methodology allows the replacement of heavy halogens (I or Br) or polar atoms (O) with the corresponding lighter and more lipophilic Cl group to block undesired reactivity or modify the properties of drug and agrochemical candidates. 相似文献
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The reaction of ethylenediamine (EDA) with ortho and/or para halogenated benzonitriles did not lead to the imidazolines expected: a competitive aromatic nucleophilic substitution (SNAr) was observed instead. The selective synthesis of these imidazolines was performed by nucleophilic addition of EDA to thiobenzamide derivatives. The difference in reactivity between the nitrile and thioamide derivatives was estimated by a frontier orbital approach at the RHF/6-31G** level which predicted a greater reactivity of substituted thiobenzamides towards the nucleophilic addition of EDA. 相似文献
8.
David Trummer Anna Giorgia Nobile Pierre-Adrien Payard Anton Ashuiev Yuya Kakiuchi Daniel Klose Gunnar Jeschke Christophe Copret 《Chemical science》2022,13(37):11091
The Union Carbide (UC) ethylene polymerization catalysts, based on chromocene dispersed on silica, show distinct features from the Phillips catalysts, but share the same heated debate regarding the structure of their active sites. Based on a combination of IR, EPR spectroscopies, labeling experiments, and DFT modeling, we identified monomeric surface-supported Cr(iii) hydrides, ( SiO)Cr(Cp)–H, as the active sites of the UC catalyst. These sites are formed in the presence of grafted and adsorbed chromocene as well as residual surface OH groups, only possible at high Cr loading, and involve a C–H activation of the Cp ring. These Cr-hydrides initiate polymerization, yielding Cr(iii) alkyl species that insert ethylene through a Cossee–Arlman-type mechanism, as evidenced by spectroscopic studies. These insights inspired the design of a well-defined analog, CpCr(CH(SiMe3)2)2 grafted on partially dehydroxylated silica, that shows similar spectroscopic and polymer structure to the UC catalyst, further supporting the proposed active site structure.A combined SOMC and DFT studies on the Union Carbide catalyst enable to propose that Cr(iii)-H, formed at high-loading, are active in ethylene polymerization. We therefore design a well-defined supported CpCr(iii)-R ethylene polymerization catalyst. 相似文献
9.
Aude Salam Jordan Rio Ilaria Ciofini Lionel Perrin Laurence Grimaud Pierre-Adrien Payard 《Molecules (Basel, Switzerland)》2022,27(21)
Controlling and understanding the Cu-catalyzed homocoupling reaction is crucial to prompt the development of efficient Cu-catalyzed cross-coupling reactions. The presence of a coordinating base (hydroxide and methoxide) enables the B-to-Cu(II) transmetalation from aryl boronic acid to CuIICl2 in methanol, through the formation of mixed Cu-(μ-OH)-B intermediates. A second B-to-Cu transmetalation to form bis-aryl Cu(II) complexes is disfavored. Instead, organocopper(II) dimers undergo a coupled transmetalation-electron transfer (TET) allowing the formation of bis-organocopper(III) complexes readily promoting reductive elimination. Based on this mechanism some guidelines are suggested to control the undesired formation of homocoupling product in Cu-catalyzed cross-coupling reactions. 相似文献
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