- Tropylium-Promoted Hydroboration Reactions: Mechanistic Insights Via Experimental and Computational Studies
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Hydroboration reaction of alkynes is one of the most synthetically powerful tools to access organoboron compounds, versatile precursors for cross-coupling chemistry. This type of reaction has traditionally been mediated by transition-metal or main group catalysts. Herein, we report a novel method using tropylium salts, typically known as organic oxidants and Lewis acids, to promote the hydroboration reaction of alkynes. A broad range of vinylboranes can be easily accessed via this metal-free protocol. Similar hydroboration reactions of alkenes and epoxides can also be efficiently catalyzed by the same tropylium catalysts. Experimental studies and DFT calculations suggested that the reaction follows an uncommon mechanistic pathway, which is triggered by the hydride abstraction of pinacolborane with tropylium ion. This is followed by a series ofin situcounterion-activated substituent exchanges to generate boron intermediates that promote the hydroboration reaction.
- Mai, Binh Khanh,Nguyen, Thanh Vinh,Ton, Nhan N. H.
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p. 9117 - 9133
(2021/07/19)
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- BISPHENOLATE TRANSITION METAL COMPLEXES, PRODUCTION AND USE THEREOF
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Bis phenolate transition metal complexes are disclosed for use in alkene polymerization, with optional chain transfer agent, to produce polyolefins.
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Page/Page column 37-38
(2019/02/15)
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- Discovery, synthesis, and structure-activity relations of 3,4-dihydro-1H-spiro(naphthalene-2,2′-piperidin)-1-ones as potassium-competitive acid blockers
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With the aim to discover a gastric antisecretory agent more potent than the existing proton pump inhibitors, novel 3,4-dihydro-1H-spiro(naphthalene-2,2′-piperidin)-1-one derivatives, which could occupy two important lipophilic pockets (described as LP-1 and LP-2) of H+,K+-ATPase and can strongly bind to the K+-binding site, were designed based on a docking model. Among the compounds synthesized, compound 4d showed a strong H+,K+-ATPase-inhibitory activity and a high stomach concentration in rats, resulting in potent inhibitory action on histamine-stimulated gastric acid secretion in rats. Furthermore, 4d exerted significant inhibitory action on histamine-stimulated gastric-acid secretion in rats with a rapid onset and moderate duration of action after the administration. These findings may lead to a new insight into the drug design of potassium-competitive acid blockers.
- Imaeda, Toshihiro,Ono, Koji,Nakai, Kazuo,Hori, Yasunobu,Matsukawa, Jun,Takagi, Terufumi,Fujioka, Yasushi,Tarui, Naoki,Kondo, Mitsuyo,Imanishi, Akio,Inatomi, Nobuhiro,Kajino, Masahiro,Itoh, Fumio,Nishida, Haruyuki
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p. 3719 - 3735
(2017/06/13)
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- Antiproliferative activity and SARs of caffeic acid esters with mono-substituted phenylethanols moiety
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A series of CAPE derivatives with mono-substituted phenylethanols moiety were synthesized and evaluated by MTT assay on growth of 4 human cancer cell lines (Hela, DU-145, MCF-7 and ECA-109). The substituent effects on the antiproliferative activity were systematically investigated for the first time. It was found that electron-donating and hydrophobic substituents at 2′-position of phenylethanol moiety could significantly enhance CAPE's antiproliferative activity. 2′-Propoxyl derivative, as a novel caffeic acid ester, exhibited exquisite potency (IC50?=?0.4?±?0.02 & 0.6?±?0.03?μM against Hela and DU-145 respectively).
- Xie, Jin,Yang, Fengzhi,Zhang, Man,Lam, Celine,Qiao, Yixue,Xiao, Jia,Zhang, Dongdong,Ge, Yuxuan,Fu, Lei,Xie, Dongsheng
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p. 131 - 134
(2016/12/27)
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- METHOD OF CONTROLLING LACTATE PRODUCTION WITH PIPERDINE-DIONE DERIVATIVES
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The invention provides novel compounds having the general formula: and tautomers and pharmaceutically acceptable salts thereof, wherein A1, A2, A3, A4, R1, R4, R5, R6, R7 and R8 are as defined herein, compositions including the compounds and methods of using the compounds.
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Page/Page column 96
(2015/11/10)
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- PIPERIDINE-DIONE DERIVATIVES
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The invention provides novel compounds having the general formula (I) and tautomers and pharmaceutically acceptable salts thereof, wherein A1, A2, A3, A4, R1, R4, R5, R6, R7 and R8 are as defined herein, compositions including the compounds and methods of using the compounds.
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Page/Page column 108
(2015/11/10)
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- Direct Ruthenium-Catalyzed Hydrogenation of Carboxylic Acids to Alcohols
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The "green" reduction of carboxylic acids to alcohols is a challenging task in organic chemistry. Herein, we describe a general protocol for generation of alcohols by catalytic hydrogenation of carboxylic acids. Key to success is the use of a combination of Ru(acac)3, triphos and Lewis acids. The novel method showed broad substrate tolerance and a variety of aliphatic carboxylic acids including biomass-derived compounds can be smoothly reduced.
- Cui, Xinjiang,Li, Yuehui,Topf, Christoph,Junge, Kathrin,Beller, Matthias
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supporting information
p. 10596 - 10599
(2015/09/02)
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- Enantioselective hydrosilylation of aromatic alkenes catalyzed by chiral bis(oxazolinyl)phenyl-rhodium acetate complexes
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Highly efficient and enantioselective hydrosilylation of aromatic alkenes catalyzed by the chiral rhodium acetate complexes with the bis(oxazolinyl)phenyl ligands has been reported that afforded chiral silane derivatives with up to 99% ee. Georg Thieme Ve
- Naito, Tatsuo,Yoneda, Takuma,Ito, Jun-Ichi,Nishiyama, Hisao
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p. 2957 - 2960
(2013/02/22)
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- Novel, one-pot procedure for the synthesis of 2-arylethanol derivatives
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An efficient one-pot synthesis of 2-arylethanol derivatives using ethylene sulfate as a C2 building block is described. High yields are obtained upon trapping of aryllithium intermediates generated by halogen-metal exchange or directed metalation with ethylene sulfate. The resulting heteroaryl or phenylethanol derivatives represent versatile building blocks for the synthesis of annulated pyran derivatives by oxa-Pictet-Spengler reaction.
- Schlaeger, Torsten,Oberdorf, Christoph,Tewes, Bastian,Wuensch, Bernhard
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p. 1793 - 1797
(2008/12/22)
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- Exploiting self-assembly for ligand-scaffold optimization: Substrate-tailored ligands for efficient catalytic asymmetric hydroboration
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(Chemical Equation Presented) Mix and match: A self-assembled ligand library (SAL XY) affords a wide range of R/S ratios in Rh-catalyzed asymmetric hydroboration (see scheme; nbd = 2,5-norbornadiene, R* is a chiral substituent). Ligand-scaffold optimization reveals "substrate- tailored" ligands that afford high regio- and enantioselectivity for a variety of ortho-substituted styrene derivatives.
- Moteki, Shin A.,Takacs, James M.
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p. 894 - 897
(2008/09/20)
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- [1,2]-Wittig rearrangement from chloromethyl ethers
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The reaction of different chloromethyl ethers 1 with an excess of lithium powder and a catalytic amount of 4,4′-di-tert-butylbiphenyl (2.5 mol %) in THF at 0 °C leads to the corresponding α-lithiomethyl ether intermediates, through a chlorine-lithium exchange, which spontaneously undergo a clean [1,2]-Wittig rearrangement affording the expected homobenzylic alcohols 2. This is the first version of this rearrangement starting from easily available chloromethyl ethers.
- Gómez, Cecilia,Maciá, Beatriz,Lillo, Victor J.,Yus, Miguel
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p. 9832 - 9839
(2007/10/03)
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- MODULATORS OF ATP-BINDING CASSETTE TRANSPORTERS
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The present invention relates to modulators of ATP-Binding Cassette ("ABC") transporters or fragments thereof, including Cystic Fibrosis Transmembrane Conductance Regulator ("CFTR"), compositions thereof, and methods therewith. The present invention also relates to methods of treating ABC transporter mediated diseases using such modulators (I) or a pharmaceutically acceptable salt thereof, wherein: Ht is a 5-membered heteroaromatic ring containing 1-4 heteroatoms selected from O, S, N or NH, wherein said ring is optionally fused to a 6-membered monocyclic or 10-membered bicyclic carbocyclic or heterocyclic, aromatic or non-aromatic ring, wherein Ht is optionally substituted with w occurrences of -WRw, wherein w is 0-5; ring A is 3-7 membered monocyclic ring having 0-3 heteroatoms selected from O, S, N, or NH, wherein ring A is optionally substituted with q occurrences of QRQ; ring B is optionally fused to 5-6 membered carbocyclic or heterocyclic, aromatic or non-aromatic ring .
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Page/Page column 139
(2010/02/13)
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- METHODS OF TREATING ALZHEIMER'S DISEASE USING ARYL ALKANOIC ACID AMIDES
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Disclosed are methods for treating Alzheimer’s disease, and other diseases, and/or inhibiting beta-secretase enzyme, and/or inhibiting deposition of A beta peptide in a mammal, by use of compounds of formula 1 (1) wherein the variables R1-R8 and X are defined herein.
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Page 184-185
(2010/02/05)
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- A new synthetic method for an acromelic acid analog, a potent neuroexcitatory kainoid amino acid, via photoinduced benzyl radical cyclization
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A new synthetic method for an acromelic acid analog, MFPA, was developed. The key step is the photoinduced benzyl radical cyclization with excellent stereoselectivity.
- Itadani, Satoshi,Takai, Shigeyuki,Tanigawa, Chieko,Hashimoto, Kimiko,Shirahama, Haruhisa
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p. 7777 - 7780
(2007/10/03)
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- Diastereoselective intramolecular meta photocycloaddition of side-chain- substituted 5-(2-methoxyphenyl)pent-1-enes
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Irradiation of a series of 5-(2-methoxyphenyl)pent-1-enes substituted with a hydroxy or trimethylsilyloxy group at the α-, β-, or γ-position of the side-chain yields in all cases meta photocycloadducts, in which the configuration at the substituted carbon atom is mainly endo. This indicates that the diastereoselectivity originates from minimization of steric interactions between the side-chain substituent and the ortho-methoxy group at the arene unit. Hydrogen bonding does not seem to be involved. The introduction of the side-chain substituents also influences the regioselectivity of the addition: The linear to angular adduct ratios are significantly increased compared to the case of the parent compound.
- Timmermans, Johan L.,Wamelink, Marc P.,Lodder, Gerrit,Cornelisse, Jan
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p. 463 - 470
(2007/10/03)
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- Construction of 3,4-disubstituted tetrahydrofuran ring by radical cyclization. A model study for kainoid synthesis
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Radical cyclization for construction of the 3,4-disubstituted tetrahydrofuran ring was attempted. The radical was produced through a charge-transfer complex under irradiation conditions.
- Itadani, Satoshi,Hashimoto, Kimiko,Shirahama, Haruhisa
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p. 105 - 108
(2007/10/03)
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- Prostanoids and related compounds. VI. Synthesis of isoindolinone derivatives possessing inhibitory activity for thromboxane A2 analog (U- 46619)-induced vasoconstriction
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We have synthesized 3-(o, m or p-substituted benzylidene)isoindolinone and 3-(2-o, m or p-substituted phenylethylidene)isoindolinone, which possess inhibitory activity for thromboxane A2 analog (U-46619)-induced vasoconstriction.
- Kato,Takemoto,Achiwa
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p. 2003 - 2006
(2007/10/02)
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