- Hydrogen-bond symmetry in zwitterionic phthalate anions: Symmetry breaking by solvation
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The cationic nitrogen of zwitterion 1 is located symmetrically with respect to its intramolecular OHO hydrogen bond. Incorporation of one 18O allows investigation of the H-bond symmetry by the NMR method of isotopic perturbation. In both CDsub
- Perrin, Charles L.,Lau, Jonathan S.
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Read Online
- CYCLIC CARBOXYLIC ACID DERIVATIVES, PREPARATION METHOD THEREOF AND PHARMACEUTICAL COMPOSITION FOR PREVENTING AND TREATING ARTHRITIS COMPRISING SAME
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The present invention relates to a cyclic carboxylic acid derivative represented by chemical formula 1, or a pharmaceutically acceptable salt, a hydrate or a solvate thereof. The cyclic carboxylic acid derivative has properties of inhibiting aggrecanase,
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Paragraph 0227; 0228
(2020/08/01)
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- BISMUTH PERFLUOROALKYLPHOSPHINATES AS LEWIS ACID CATALYSTS
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The invention relates to bismuth perfluoroalkylphosphinates as Lewis acid catalysts, the compounds, and processes for the preparation thereof. [in-line-formulae]ArxBi[OP(O)(Rf)2]3-x??(Ia),[/in-line-formulae] [in-line-formulae]Ar3Bi[OP(O)(Rf)2]2??(Ib).[/in-line-formulae]
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Paragraph 0134; 0135
(2018/10/19)
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- Bismuth Perfluoroalkylphosphinates: New Catalysts for Application in Organic Syntheses
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Commercially available BiPh3was treated with perfluoroalkylphosphinic acids [for example, (C2F5)2P(O)OH] to generate novel, highly Lewis acidic bismuth(III) perfluoroalkylphosphinates of the type PhxBi[RF2PO2]3?x(x=0, 1, 2) (RF=-C2F5, -C4F9). The first bismuth(V) perfluoroalkylphosphinate, Ph3Bi[(C2F5)2PO2]2, was synthesized from Ph3BiCl2and Ag[(C2F5)2PO2]. Examples for the successful application of the catalytically active bismuth(III) and bismuth(V) phosphinates in carbon–carbon bond forming reactions, such as Friedel–Crafts acylation and alkylation, Diels–Alder, Strecker and Mannich reaction, are presented.
- Solyntjes, Sven,Neumann, Beate,Stammler, Hans-Georg,Ignat'ev, Nikolai,Hoge, Berthold
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p. 1568 - 1575
(2017/02/10)
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- Sustainable production of pyromellitic acid with pinacol and diethyl maleate
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Herein, we report an unprecedented and sustainable route to synthesize pyromellitic acid (PMA), a monomer of polyimide, with pinacol and diethyl maleate which can be derived from lignocellulose. Analogously, a sustainable route to trimellitic acid (TMA) was also developed using pinacol and acrylate as the feedstocks.
- Hu, Yancheng,Li, Ning,Li, Guangyi,Wang, Aiqin,Cong, Yu,Wang, Xiaodong,Zhang, Tao
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supporting information
p. 1663 - 1667
(2017/06/05)
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- Pentacenequinone-stabilized silver nanoparticles: A reusable catalyst for the diels-alder [4 + 2] cycloaddition reactions
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Silver nanoparticles (AgNPs) stabilized by aggregates of derivative 4 have been used as catalyst for the construction of synthetically and biologically important [4 + 2] cycloadducts at room temperature.
- Chopra, Radhika,Sharma, Kamaldeep,Kumar, Manoj,Bhalla, Vandana
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supporting information
p. 1039 - 1046
(2016/02/18)
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- Solvent-free Diels-Alder reaction in a closed batch system
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Solvent-free Diels-Alder reactions were carried out by heating a mixture of a volatile diene, such as 1,3-butadiene, isoprene, or 2,3-dimethyl-1,3- butadiene, and a dienophile, such as methyl vinyl ketone, methyl acrylate, or maleic anhydride, in a closed batch reactor. High yields of Diels-Alder products were obtained without using solvents and catalysts within a short reaction time in most of the reactions. In particular, several reactions of dienophiles with 1,3-butadiene, which is known as a diene with low reactivity because of its gaseous form, also proceeded with high yields of Diels-Alder products in the closed batch reactor under conditions pressured by the reactant vapor. Solvent-free reactions provided high yields compared to reactions in solvent since the reaction heat directly resulted in increasing the reaction temperature and pressure. Energy in the exothermic reaction was used effectively in the closed batch system under solvent-free conditions.
- Sun, Daolai,Sato, Fumiya,Yamada, Yasuhiro,Sato, Satoshi
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p. 276 - 282
(2013/05/08)
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- Synthesis and physicochemical properties of strong electron acceptor 14,14,15,15-tetracyano-6,13-pentacenequinodimethane (TCPQ) diimide
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14,14,15,15-Tetracyano-6,13-pentacenequinodimethane (TCPQ) diimide, a new tetracyanoquinodimethane analogue with extended conjugation and imide substituents, was synthesized by double Diels-Alder reactions and a Knoevenagel condensation reaction. Experimental results showed that TCPQ diimide has a low LUMO energy level (-4.03 eV) and good solubility in organic solvents.
- Li, Jie,Xiong, Yu,Wu, Qinghe,Wang, Shitao,Gao, Xike,Li, Hongxiang
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p. 6136 - 6139,4
(2020/09/16)
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- A Tin-tungsten mixed oxide as an efficient heterogeneous catalyst for C-C Bond Bond-Forming reactions
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The tin-tungsten mixed oxide prepared by the calcination of the tin-tungsten hydroxide precursor with a Sn/W molar ratio of 2 at 800 °C (SnW2-800) acts as an effective and reusable solid catalyst for C-C bond-forming reactions, such as the cyclization of citronellal, the Diels-Alder reaction, and the cyanosilylation of carbonyl compounds with trimethylsilyl cyanide (TMSCN). Various kinds of structurally diverse aliphatic, aromatic, and unsaturated, heteroatom-containing substrates could be converted into the desired products in high to excellent yields. The observed catalyses for these reactions were truly heterogeneous and the recovered catalyst could be reused several times without an appreciable loss of its high catalytic performance. The Bronsted acid sites generated on the aggregated polytungstate species on SnW2-800 likely play an important role in the C-C bond-forming reactions.
- Ogasawara, Yoshiyuki,Uchida, Sayaka,Yamaguchi, Kazuya,Mizuno, Noritaka
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experimental part
p. 4343 - 4349
(2009/11/30)
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- Novel water-soluble sedative-hypnotic agents: Isoindolin-1-one derivatives
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We developed new intravenous sedative-hypnotic compounds with the isoindolin-1-one skeleton focusing on the water-soluble property and in vivo safety. We synthesized approximately 170 derivatives and evaluated their hypnotic effects by intravenous administration of the compounds to mice. A series of the 2-phenyl-3-[2-(4-methyl-1-piperazinyl)-2-oxoethyl]isoindolin-1-one analogs, 3(-), 5(-), 27(-), and 47(-) [JM-1232(-)], showed potent sedative-hypnotic activity with good water solubility and a wide safety margin. The hypnotic doses (HD50s) of these 4 compounds when administered to mice were 2.35, 1.90, 2.17, and 3.12 mg/kg, respectively, and the lethal doses (LD50s) were 88.67, 64.69, >120, and >120 mg/kg, respectively. The therapeutic indexes (LD50/HD50) were 37.73, 34.05, >55.30, and >38.46, respectively. Among these compound, 47(-) [JM-1232(-)] is being considered as the most potential candidate for clinical trials in humans.
- Kanamitsu, Norimasa,Osaki, Takashi,Itsuji, Yutaka,Yoshimura, Masakazu,Tsujimoto, Hisashi,Soga, Manabu
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p. 1682 - 1688
(2008/12/21)
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- NEUROGENIC PAIN CONTROL AGENT COMPOSITION
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The instant application provides a pharmaceutical composition for controlling neuropathic pain, which comprises a compound of formula: or a salt thereof.
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Page/Page column 12
(2008/06/13)
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- Modular microreaction systems for homogeneously and heterogeneously catalyzed chemical synthesis
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Until now, microreaction devices designed for a specific type of reaction were used mainly for highly exothermic, very fast reactions. Described is a modular microreaction system and its application to representative homogeneous and heterogeneous reactions important in organic synthesis. The modular microreaction system allows continuous flow processes to be optimized and employed effectively in the chemical laboratory. The modular microreaction systems proved also versatile for syntheses requiring moderate reaction times, thus extending their application to a large fraction of organic reactions. The use of the modular and cleanable microreaction systems to rapidly develop optimized reaction conditions provides an excellent basis for the development of many chemical transformations scalable from milligram to ton production quantities.
- Snyder, Daniel A.,Noti, Christian,Seeberger, Peter H.,Schael, Frank,Bieber, Thomas,Rimmel, Guido,Ehrfeld, Wolfgang
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- Monomeric metal aqua complexes in the interlayer space of montmorillonites as strong Lewis acid catalysts for heterogeneous carbon-carbon bond-forming reactions
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Montmorillonite-enwrapped copper and scandium catalysts (Cu2-- and Sc3+-monts) were easily prepared by treating Na--mont with the aqueous solution of the copper nitrate and scandium triflate, respectively. The resulting Cu2+- and Sc3+-monts showed outstanding catalytic activities for a variety of carbon-carbon bond-forming reactions, such as the Michael reaction, the Sakurai-Hosomi allylation, and the Diels-Alder reaction, under solvent-free or aqueous conditions. The remarkable activity of the mont catalysts is attributable to the negatively charged silicate layers that are capable of stabilizing metal cations. Furthermore, these catalysts were reusable without any appreciable loss in activity and selectivity. The Cu2+-mont-catalyzed Michael reaction proceeds via a ternary complex in which both the 1,3-dicarbonyl compound and the enone are coordinated to a Lewis acid Cu2+ center.
- Kawabata, Tomonori,Kato, Masaki,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
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p. 288 - 297
(2007/10/03)
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- ISOINDOLINE DERIVATIVE
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Provided is a novel isoindoline compound of the formula (I): The compound is useful for anesthesia by inducing sedation in a mammal.
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Page/Page column 17
(2008/06/13)
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- Ionic liquids as powerful media in scandium triflate catalysed Diels-Alder reactions: Significant rate acceleration, selectivity improvement and easy recycling of catalyst
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Ionic liquids act as powerful media (or additives) in scandium triflate catalysed Diels-Alder reactions not only for facilitating of catalyst recovery but also for accelerating reaction rate and improving selectivity.
- Song,Shim,Roh,Lee,Choi
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p. 1122 - 1123
(2007/10/03)
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- Aqueous catalysis: Methylrhenium trioxide (MTO) as a homogeneous catalyst for the Diels-Alder reaction
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The title compound proves to be an effective and efficient catalyst for the Diels-Alder reaction when the dienophile is an α,β-unsaturated ketone or aldehyde. It is especially effective in water. Equal amounts of any such dienophile and any of six representative dienes (isoprene, 2-methyl-1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, cyclopentadiene, 1,2,3,4,5-pentamethylcyclopentadiene, and 1,3-cyclohexadiene) were used, along with 1% MTO. The reactions gave usually > 90% isolated yield of the cycloaddition product except for the larger dienophiles. Nearly exclusively, there was formed one product isomer, the same one that usually predominates. The reactions were often run in chloroform (mostly) and in other organic solvents. A select number were carried out in water, where the reactions gave a greater product yield in a considerably shorter time. Water, itself, is known to enhance the rates of Diels-Alder reactions, but MTO exerts an additional accelerating effect. Kinetics studies were carried out to show that the rate is proportional to the catalyst concentration. The products do not inhibit the reaction. The desirability of MTO as a Diels-Alder catalyst stems from a combination of favorable properties: the inertness to air/oxygen, the tolerance for many substrates, the use of an aqueous medium, and the absence of product inhibition. The initial step appears to be the (weak) coordination of the carbonyl oxygen to the electropositive rhenium center. Steric crowding around rhenium inhibits reactions of the larger dienophiles.
- Zhu, Zuolin,Espenson, James H.
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p. 3507 - 3512
(2007/10/03)
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- Studies on the Chemistry of Isoindoles and Isoindolenines, XXVIII. - 3-Alkoxy-1H-isoindoles, Syntheses and Properties
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3-Alkoxy-1H-isoindoles 1 bearing substituents at the carboxylic moiety have been synthesized from substituted 2,3-dihydro-1H-isoindol-1-ones 4 by regiospecific O-alkylation to 5 with trialkyloxonium tetrafluoroborates or methyl trifluoroborates or methyl trifluoromethanesulfonate and subsequent NH deprotonation.According to the spectroscopic properties the semicyclic alkyl imidates 1 exist exclusively in the benzoid 1H structure; the tautomeric o-quinonoid 2H structure 2 cannot be detected by spectroscopic means.
- Hennige, Hans,Kreher, Richard P.,Konrad, Michael,Jelitto, Frank
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p. 243 - 252
(2007/10/02)
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- Reaktivity of Substituted 1,3-Butadienes in Diels-Alder-Reactions
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Kinetic data for the reaction of substituted 1,3-dienes with tetracyanoethylene (TCNE) and other dienophiles are interpreted in terms of the FMO-model.While the expectations are fulfilled qualitatively, the kinetic data cannot be correlated quantitatively.This shows that in Diels-Alder reactions besides HOMO-LUMO separation other factors play an important role, for instance the 1,4-distance in the diene and the conformational equilibrium cisoid transoid of the diene.The kinetic data are in accord with a one-step mechanism of the cycloaddition reaction.
- Ruecker, Christa,Lang, Dietrich,Sauer, Juergen,Friege, Henning,Sustmann, Reiner
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p. 1663 - 1690
(2007/10/02)
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