- Evaluation of the Structure-Activity Relationship of Microtubule-Targeting 1,2,4-Triazolo[1,5- a]pyrimidines Identifies New Candidates for Neurodegenerative Tauopathies
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Studies in tau and Aβ plaque transgenic mouse models demonstrated that brain-penetrant microtubule (MT)-stabilizing compounds, including the 1,2,4-triazolo[1,5-a]pyrimidines, hold promise as candidate treatments for Alzheimer's disease and related neurodegenerative tauopathies. Triazolopyrimidines have already been investigated as anticancer agents; however, the antimitotic activity of these compounds does not always correlate with stabilization of MTs in cells. Indeed, previous studies from our laboratories identified a critical role for the fragment linked at C6 in determining whether triazolopyrimidines promote MT stabilization or, conversely, disrupt MT integrity in cells. To further elucidate the structure-activity relationship (SAR) and to identify potentially improved MT-stabilizing candidates for neurodegenerative disease, a comprehensive set of 68 triazolopyrimidine congeners bearing structural modifications at C6 and/or C7 was designed, synthesized, and evaluated. These studies expand upon prior understanding of triazolopyrimidine SAR and enabled the identification of novel analogues that, relative to the existing lead, exhibit improved physicochemical properties, MT-stabilizing activity, and pharmacokinetics.
- Oukoloff, Killian,Nzou, Goodwell,Varricchio, Carmine,Lucero, Bobby,Alle, Thibault,Kovalevich, Jane,Monti, Ludovica,Cornec, Anne-Sophie,Yao, Yuemang,James, Michael J.,Trojanowski, John Q.,Lee, Virginia M.-Y.,Smith, Amos B.,Brancale, Andrea,Brunden, Kurt R.,Ballatore, Carlo
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p. 1073 - 1102
(2021/02/03)
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- Enantioselective Desymmetrization of 2-Aryl-1,3-propanediols by Direct O-Alkylation with a Rationally Designed Chiral Hemiboronic Acid Catalyst That Mitigates Substrate Conformational Poisoning
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Enantioselective desymmetrization by direct monofunctionalization of prochiral diols is a powerful strategy to prepare valuable synthetic intermediates in high optical purity. Boron acids can activate diols toward nucleophilic additions; however, the design of stable chiral catalysts remains a challenge and highlights the need to identify new chemotypes for this purpose. Herein, the discovery and optimization of a bench-stable chiral 9-hydroxy-9,10-boroxarophenanthrene catalyst is described and applied in the highly enantioselective desymmetrization of 2-aryl-1,3-diols using benzylic electrophiles under operationally simple, ambient conditions. Nucleophilic activation and discrimination of the enantiotopic hydroxy groups on the diol substrate occurs via a defined chairlike six-membered anionic complex with the hemiboronic heterocycle. The optimal binaphthyl-based catalyst 1g features a large aryloxytrityl group to effectively shield one of the two prochiral hydroxy groups on the diol complex, whereas a strategically placed "methyl blocker"on the boroxarophenanthrene unit mitigates the deleterious effect of a competing conformation of the complexed diol that compromised the overall efficiency of the desymmetrization process. This methodology affords monoalkylated products in enantiomeric ratios equal or over 95:5 for a wide range of 1,3-propanediols with various 2-aryl/heteroaryl groups.
- Estrada, Carl D.,Ang, Hwee Ting,Vetter, Kim-Marie,Ponich, Ashley A.,Hall, Dennis G.
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supporting information
(2021/04/07)
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- Radical Addition Enables 1,2-Aryl Migration from a Vinyl-Substituted All-Carbon Quaternary Center
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An efficient method for photocatalytic perfluoroalkylation of vinyl-substituted all-carbon quaternary centers involving 1,2-aryl migration has been developed. The rearrangement reactions use fac-Ir(ppy)3, visible light and commercially available fluoroalkyl halides and can generate valuable multisubstituted perfluoroalkylated compounds in a single step that would be challenging to prepare by other methods. Mechanistically, the photoinduced alkyl radical addition to an alkene leads to the migration of a vicinal aryl substituent from its adjacent all-carbon quaternary center with the concomitant generation of a C-radical bearing two electron-withdrawing groups that is further reduced by a hydrogen donor to complete the domino sequence.
- Li, Zexian,Shi, Zhuangzhi,Wang, Minyan
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supporting information
p. 186 - 190
(2020/11/02)
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- OXIDATIVE COUPLING OF ARYL BORON REAGENTS WITH SP3-CARBON NUCLEOPHILES, AND AMBIENT DECARBOXYLATIVE ARYLATION OF MALONATE HALF-ESTERS VIA OXIDATIVE CATALYSIS
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Described herein are methods of oxidative coupling of aryl boron reagents with sp3-carbon nucleophiles, and ambient decarboxylative arylation of malonate half-esters via oxidative catalysis.
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Paragraph 0142; 0143; 0178
(2018/07/29)
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- Palladium-Catalyzed Asymmetric Allylic Alkylation of 4-Substituted Isoxazolidin-5-ones: Straightforward Access to β2,2-Amino Acids
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We report here an unprecedented and highly enantioselective palladium-catalyzed allylic alkylation applied to 4-substituted isoxazolidin-5-ones. Ultimately, the process provides a straightforward access to β2,2-amino acids bearing an all-carbon quaternary stereogenic center in great yields and a high degree of enantioselectivity.
- Nascimento de Oliveira, Marllon,Arseniyadis, Stellios,Cossy, Janine
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supporting information
p. 4810 - 4814
(2018/03/21)
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- Oxidative Coupling of Aryl Boron Reagents with sp3-Carbon Nucleophiles: the Enolate Chan-Evans-Lam Reaction
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Reported is a versatile new oxidative method for the arylation of activated methylene species. Under mild reaction conditions (RT to 40 C), Cu(OTf)2 mediates the selective coupling of functionalized aryl boron species with a variety of stabilized sp3-nucl
- Moon, Patrick J.,Halperlin, Heather M.,Lundgren, Rylan J.
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supporting information
p. 1894 - 1898
(2016/08/31)
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- Oxidative coupling of aryl boron reagents with sp3-carbon nucleophiles: The enolate chan–evans–lam reaction
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Reported is a versatile new oxidative method for the arylation of activated methylene species. Under mild reaction conditions (RT to 40°C), Cu(OTf)2mediates the selective coupling of functionalized aryl boron species with a variety of stabilized sp3-nucleophiles. Tertiary malonates and amido esters can be employed as substrates to generate quaternary centers. Complementing either traditional cross-coupling or SNAr protocols, the transformation is chemoselective in the presence of halogen electrophiles, including aryl bromides and iodides. Substrates bearing amide, sulfonyl, and phosphonyl groups, which are not amenable to coupling under mild Hurtley-type conditions, are suitable reaction partners.
- Moon, Patrick J.,Halperin, Heather M.,Lundgren, Rylan J.
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supporting information
p. 1894 - 1898
(2016/12/03)
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- Arylation of diethyl malonate and ethyl cyanoacetate catalyzed by palladium/di-tert-butylneopentylphosphine
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α-Arylated carbonyl derivatives are important structural motifs in many natural products and pharmaceutically active compounds. Although arylation of simple monocarbonyl compounds is a well-established methodology, metal-catalyzed arylation of β-dicarbonyl derivatives is significantly more challenging. The ability of β-dicarbonyl anions to bind to palladium in a κ2-O,O mode, rather than the κ1-C-bound mode required for bond formation, often results in the deactivation of catalyst systems. The C-bound form of the enolate can be favored through the use of sterically demanding ligands. Herein, we report that the sterically demanding di-tert-butylneopentylphosphine (DTBNpP) ligand in combination with Pd(dba)2 provides an effective catalyst for the coupling of aryl bromides and chlorides with diethyl malonate. The Pd/DTBNpP system also catalyzes the coupling of aryl bromides with ethyl cyanoacetate.
- Semmes, Jeffrey G.,Bevans, Stephanie L.,Mullins, C. Haddon,Shaughnessy, Kevin H.
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supporting information
p. 3447 - 3450
(2015/02/05)
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- HETEROARYL LINKED QUINOLINYL MODULATORS OF RORyt
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The present invention comprises compounds of Formula I. wherein: R1, R2, R3, R4, R5, R6, R7, R8, and R9 are defined in the specification. The invention also comprises a method of treating or ameliorating a syndrome, disorder or disease, wherein said syndrome, disorder or disease is rheumatoid arthritis or psoriasis. The invention also comprises a method of modulating RORγt activity in a mammal by administration of a therapeutically effective amount of at least one compound of claim 1.
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Paragraph 0467; 0468
(2014/05/07)
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- New efficient ligand-free, copper nanoparticle catalyzed coupling reactions of aryl halides with diethyl malonate to produce α-arylation of malonates
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Recently synthesized copper nanoparticles (Cu NP) were used to catalyze coupling of aryl halides with diethyl malonates to produce α-aryl malonates. Synthetic conditions, including solvents, relative amounts of reactants, catalyst, and temperature, etc. h
- Pai, Gita,Chattopadhyay, Asoke P.
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p. 1475 - 1482
(2013/06/27)
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- Enzymatic desymmetrization of prochiral 2-substituted-1,3-diamines: Preparation of valuable nitrogenated compounds
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A wide range of prochiral 1, 3-diamines were first efficiently synthesized and subsequently desymmetrized by using lipase from Pseudomonas cepacia as catalyst and diallyl carbonate as alkoxycarbonylating agent. In all cases, the amino carbamates of R-configuration were recovered. Final selective cleavage of the N-allyloxycarbonyl moiety was carried out under mild reaction conditions, which demonstrates the high versatility and potential of this chemoenzymatic route as a source of intermediates in the synthesis of related optically active nitrogenated derivatives.
- Rios-Lombardia, Nicolas,Busto, Eduardo,Garcia-Urdiales, Eduardo,Gotor-Fernandez, Vicente,Gotor, Vicente
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supporting information; body text
p. 2571 - 2574
(2009/07/25)
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- First desymmetrization of 1,3-propanediamine derivatives in organic solvent. Development of a new route for the preparation of optically active amines
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The chemical synthesis and enzymatic desymmetrization of a panel of prochiral diamines have been successfully described for the first time using lipases in organic solvents. A family of 2-aryl-1,3-propanediamines has been obtained with high enantiopurity and good yields in the PSL-catalyzed reaction using diallyl carbonate in 1,4-dioxane.
- Bustos, Eduardo,Gotor-Fernandez, Vicente,Montejo-Bernardo, Jose,Garcia-Granda, Santiago,Gotor, Vicente
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p. 4203 - 4206
(2008/02/14)
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- Room-temperature copper-catalyzed α-arylation of malonates
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An effective method in targeting α-aryl malonates is reported. In the presence of a catalytic amount of 2-picolinic acid and Cul, the coupling of aryl iodides with diethyl malonate proceeds smoothly even at room temperature. The high levels of functional group compatibility and exceptionally mild reaction conditions offer this an attractive protocol in accessing a variety of arylated malonates.
- Yip, Sau Fan,Cheung, Hong Yee,Zhou, Zhongyuan,Kwong, Fuk Yee
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p. 3469 - 3472
(2008/02/12)
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- Unusual Tethering Effects in the Schmidt Reaction of Hydroxyalkyl Azides with Ketones: Cation-π and Steric Stabilization of a Pseudoaxial Phenyl Group
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The Lewis acid-promoted reactions of chiral 2-aryl-3-azido-1-propanols with 4-substituted cyclohexanones lead to iminium ethers and ultimately caprolactams (following a hydrolysis step). In this study, it is shown that these reactions afford variable ratios of products, depending on the electronic nature of the phenyl group. These results are interpreted in the context of a cation?π stabilizing effect in the product-determining reaction intermediate. Remarkably, the best selectivity was obtained when an azidopropanol reagent containing a quaternary center was used; a control experiment showed that the high selectivity observed in this result depended upon the free rotation of the pseudoaxial aromatic group in the intermediate that affords the major product. Copyright
- Katz, Christopher E.,Aube, Jeffrey
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p. 13948 - 13949
(2007/10/03)
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- Palladium-catalyzed arylation of malonates and cyanoesters using sterically hindered trialkyl- and ferrocenyldialkylphosphine ligands
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Palladium-catalyzed reactions of aryl bromides and chlorides with two common stabilized carbanions - enolates of dialkyl malonates and alkyl cyanoesters - are reported. An exploration of the scope of these reactions was conducted, and the processes were shown to occur in a general fashion. Using P(t-Bu)3 (1), the pentaphenylferrocenyl ligand (Ph5C5)Fe(C5H4)P(t-Bu) 2 (2), or the adamantyl ligand (1-Ad)P(t-Bu)2 (3), reactions of electron-poor and electron-rich, sterically hindered and unhindered aryl bromides and chlorides were shown to react with diethyl malonate, di-tertbutyl malonate, diethyl fluoromalonate, ethyl cyanoacetate, and ethyl phenylcyanoacetate. Although alkyl malonates and ethyl alkylcyanoacetates did not react with aryl halides using these catalysts, the same products were formed conveniently in one pot from diethylmalonate by cross-coupling of an aryl halide in the presence of excess base and subsequent alkylation.
- Beare, Neil A.,Hartwig, John F.
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p. 541 - 555
(2007/10/03)
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- First heterogeneously palladium catalysed α-arylation of diethyl malonate
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Pd exchanged NaY zeolites ([Pd(0)]-, [Pd(II)]- and entrapped [Pd(NH3)4]) exhibit a good activity towards the α-arylation of carbonyl compounds using different para-substituted aryl bromides. Low Pd-concentrations (only 2 mol%) are required to observe interesting activity. The catalysts can easily be separated from the reaction mixture and reused without any loss in activity. For large-scale applications the alternative use of an insoluble base as K2CO3 seems to be promising. The electronic nature of the aryl halides plays a limited role concerning the rate of the reaction.
- Djakovitch, Laurent,K?hler, Klaus
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p. 101 - 107
(2007/10/03)
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