79432-87-4Relevant academic research and scientific papers
Z-Selective phosphine promoted 1,4-reduction of ynoates and propynoic amides in the presence of water
Drikermann, Denis,Kupfer, Stephan,Seifert, Fabian,Steinmetzer, Johannes,Vilotijevic, Ivan,Zi, You
, p. 6092 - 6097 (2021/07/21)
Phosphine-mediated reductions of substituted propynoic esters and amides in the presence of water yield the partially reduced α,β-unsaturated esters and amides with highZ-selectivity. The competitivein situ ZtoE-isomerization of the product in some cases lowers theZtoEratios of the isolated α,β-unsaturated carbonyl products. Reaction time and the amounts of phosphine and water in the reaction mixture are the key experimental factors which control the selectivity by preventing or reducing the rates ofZ- toE-product isomerization. Close reaction monitoring enables isolation of theZ-alkenes with high selectivities. The computational results suggest that the reactions could be highlyZ-selective owing to the stereoselective formation of theE-P-hydroxyphosphorane intermediate.
NOVEL LXR MODULATORS WITH BICYCLIC CORE MOIETY
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Page/Page column 55-56, (2020/01/24)
The present invention relates to bicyclic compounds (e.g. indoles) containing a sulfonyl moiety, which bind to the liver X receptor (LXRα and/or LΧΚβ) and act preferably as inverse agonists of LXR.
Templating effect of carbon nanoforms on highly cross-linked imidazolium network: Catalytic activity of the resulting hybrids with Pd nanoparticles
Campisciano, Vincenzo,Calabrese, Carla,Liotta, Leonarda Francesca,La Parola, Valeria,Spinella, Alberto,Aprile, Carmela,Gruttadauria, Michelangelo,Giacalone, Francesco
, (2019/05/10)
Two different carbon nanoforms (CNFs), namely multi-walled carbon nanotubes (MWCNTs) and carbon nanohorns (CNHs), have been chosen as support for the direct polymerization of a bis-vinylimidazolium salt. Transmission electron microscopy analyses revealed a templating effect of the CNFs on the growth of the polymeric network, which perfectly covers their whole surfaces creating a cylindrical or spherical coating for MWCNTs and CNHs, respectively. Subsequently, the CNFs-polyimidazolium have been used as stabilizers for Pd nanoparticles (Pd NPs), and the obtained materials have been characterized by means of analytical and spectroscopic techniques and then employed as easily recoverable and recyclable catalysts for Suzuki and Heck reactions. Quantitative conversions have been obtained in almost all the explored reactions, even employing low loading of catalyst (down to 0.007 mol%). Suzuki reactions were carried out in pure water under aerobic conditions. Both materials showed excellent activity and recyclability for the investigated C-C coupling reactions, with the CNHs-based material resulting slightly more active than the MWCNTs-based one due to a higher superficial exposure of Pd NPs.
Enantioselective [2+2] Cycloadditions of Cinnamate Esters: Generalizing Lewis Acid Catalysis of Triplet Energy Transfer
Daub, Mary Elisabeth,Jung, Hoimin,Lee, Byung Joo,Won, Joonghee,Baik, Mu-Hyun,Yoon, Tehshik P.
supporting information, p. 9543 - 9547 (2019/06/24)
We report the enantioselective [2+2] cycloaddition of simple cinnamate esters, the products of which are useful synthons for the controlled assembly of cyclobutane natural products. This method utilizes a cocatalytic system in which a chiral Lewis acid accelerates the transfer of triplet energy from an excited-state Ir(III) photocatalyst to the cinnamate ester. Computational evidence indicates that the principal role of the Lewis acid cocatalyst is to lower the absolute energies of the substrate frontier molecular orbitals, leading to greater electronic coupling between the sensitizer and substrate and increasing the rate of the energy transfer event. These results suggest Lewis acids can have multiple beneficial effects on triplet sensitization reactions, impacting both the thermodynamic driving force and kinetics of Dexter energy transfer.
DIHYDROPYRIMIDINE COMPOUNDS AND USES THEREOF IN MEDICINE
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Paragraph 00315, (2019/05/10)
Provided herein are a dihydropyrimidine compound and use as a medicament, especially application as a medicament used for treating and preventing hepatitis B. Specifically, provided herein is a compound having Formula (I) or (Ia), or a stereisomer, a tautomer, an N-oxide, a solvate, a metabolite, a pharmaceutically acceptable salt or a prodrug thereof, wherein the variables of the formulas are as defined in the specification. Also provided herein is use of the compound having Formula (I) or (Ia), or an enantiomer, a diastereoisomer, a tautomer, a hydrate, a solvate, or a pharmaceutically acceptable salt thereof as a medicament, especially use as a medicament for treating and preventing hepatitis B.
Dihydropyridine compound and application thereof to drugs
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Paragraph 0796-0799, (2019/05/08)
The invention relates to a dihydropyridine compound and application of the dihydropyridine compound serving as a drug, in particular to application of the dihydropyridine compound serving as a drug for treating and preventing hepatitis B. Specifically, the invention relates to the compound shown as the general formula (I) or (Ia) (please see the specifications for the general formula (I) or (Ia))or stereoisomers, tautomer, a nitrogen oxide, solvate, metabolites and medically acceptable salt of the compound or a prodrug of the compound, wherein all variables are defined in the specification. The invention further relates to application of the compound shown as the general formula (I) or (Ia) or enantiomers, non-enantiomers, the tautomer, hydrates, the solvate or the medically acceptable salt of the compound serving as drugs, in particular to application of the compound or the enantiomers, the non-enantiomers, the tautomer, the hydrates, the solvate or the medically acceptable salt of the compound serving as the drugs for treating and preventing hepatitis B.
Using non-covalent interactions to direct regioselective 2+2 photocycloaddition within a macrocyclic cavitand
Nguyen, Nga,Clements, Aspen Rae,Pattabiraman, Mahesh
, p. 2433 - 2443 (2016/03/19)
The relative orientation of guests within ternary inclusion complexes is governed by the host-guest and guest-guest supramolecular interactions. Selectivity in 2+2 photocycloaddition between two alkenes included within a macrocyclic cavitand (γ-cyclodextrin) can be controlled using non-covalent interactions. In this manuscript, we report cavitand-mediated control of regioselectivity between alkyl cinnamates using non-covalent interactions. Using this method, we have shown that regioselectivity can be switched completely from a head-to-head dimer to a head-to-tail dimer. The reactions were also stereoselective in most cases. Stoichiometry experiments were performed to explore relative stabilities of the complexes, which indicate that the ternary complex is more stable than others. Selectivity in the photocycloaddition reaction was also applied retrospectively to deduce intermolecular orientations. Time-dependent conversion study we performed indicates that the observed reactivity of alkenes is representative of the intermolecular orientations in the bulk of the complex medium. Experimental observations and computational studies were used to qualitatively understand the complex structures, and relative magnitudes of the weak interactions. The reactions of complexes were studied in slurry form, and the extent of reaction control suggests a solid-state-like behavior.
High Loading of Pd Nanoparticles by Interior Functionalization of MOFs for Heterogeneous Catalysis
Gole, Bappaditya,Sanyal, Udishnu,Banerjee, Rahul,Mukherjee, Partha Sarathi
, p. 2345 - 2354 (2016/03/19)
In this report, the issue related to nanoparticle (NP) agglomeration upon increasing their loading amount into metal-organic frameworks (MOFs) has been addressed by functionalization of MOFs with alkyne groups. The alkynophilicity of the Pd2+ (or other noble metals) ions has been utilized successfully for significant loading of Pd NPs into alkyne functionalized MOFs. It has been shown here that the size and loading amount of Pd NPs are highly dependent on the surface area and pore width of the MOFs. The loading amount of Pd NPs was increased monotonically without altering their size distribution on a particular MOF. Importantly, the distinct role of alkyne groups for Pd2+ stabilization has also been demonstrated by performing a control experiment considering a MOF without an alkyne moiety. The preparation of NPs involved two distinct steps viz. adsorption of metal ions inside MOFs and reduction of metal ions. Both of these steps were monitored by microscopic techniques. This report also demonstrates the applicability of Pd@MOF NPs as extremely efficient heterogeneous catalysts for Heck-coupling and hydrogenation reactions of aryl bromides or iodides and alkenes, respectively.
Compositions containing ionic liquids and their uses, in particular in organic synthesis
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Page/Page column 45; 46; 47, (2016/10/17)
An ionic liquid is used as liquid matrix for organic synthesis in homogeneous phase on soluble support, the ionic liquid being presented in liquid or solid form at ambient temperature, of formula A1+X1?, A1+ representing a cation, functional or non-functional, or a mixture of cations in which either none of the cations is functional or at least one of the cations is functional, and X1? an anion, functional or non-functional, or a mixture of anions in which either none of the anions is functional or at least one of the anions is functional.
Scope and Limitation of the Microwave-Assisted Catalytic Wittig Reaction
Hoffmann, Marcel,Deshmukh, Sunetra,Werner, Thomas
, p. 4532 - 4543 (2015/07/27)
We have developed a microwave-assisted catalytic Wittig reaction. In this paper, we give full account of the scope and limitations of this reaction. A screening of various commercially available phosphine oxides as precatalysts revealed Bu3P=O to be the most promising candidate. We tested 10 silanes for the in situ reduction of the phosphine oxide to generate Bu3P as the actual catalyst. Different epoxides were tested as masked bases. In this context, cyclohexene oxide as well as butylene oxide proved to be suitable. The reaction could be carried out at 125 C, but higher yields and E/Z selectivities were obtained at 150 °C. Under the optimised reaction conditions, more than 40 examples for the conversion of various aldehydes into the corresponding alkenes are reported. The products were obtained in yields of up to 88 with high E selectivities. Moreover, we also describe the further screening of several chiral phosphines as catalysts for the microwave-assisted enantioselective catalytic Wittig reaction. The scope and limitations of the microwave-assisted catalytic Wittig reaction have been evaluated with respect to the catalyst, silane, solvent, reaction conditions, and substrates.
