- Copper(I) Iodide-Catalyzed (Het)arylation of Diethyl Malonate with (Het)aryl Bromides by Using 1,3-Benzoxazole as a Ligand
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An efficient Ullmann-type coupling of aryl bromides with diethyl malonate in the presence of copper(I) iodide and 1,3-benzoxazole is presented. This method has a broad substrate scope (heterocyclic and phenyl bromides) and good functional-group tolerance (OMe, Me, Ac, CN, NO 2, F, and Cl). Moreover, less time is needed to reach full conversion (3-9 hours).
- Zeng, Yu,Zheng, Hao-Liang,Yang, Zhao,Liu, Cheng-Kou,Fang, Zheng,Guo, Kai
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- C-arylation reactions catalyzed by CuO-nanoparticles under ligand free conditions
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CuO-nanoparticles were found to be an excellent heterogeneous catalyst for C-arylation of active methylene compounds using various aryl halides. The products were obtained in good to excellent yield. The catalyst can be recovered and reused for four cycles with almost no loss in activity.
- Kidwai, Mazaahir,Bhardwaj, Saurav,Poddar, Roona
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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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- EQUILIBRIUM ACIDITIES AND HOMOLYTIC BOND DISSOCIATION ENTHALPIES OF THE ACIDIC C-H BONDS IN DIALKYL MALONATES AND RELATED COMPOUNDS
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The equilibrium acidities, pKHA, of 18 dialky malonates, five alkyl 2-cyanoacetates and nine malononitriles and the oxidation potentials of their conjugate anions, Eox(A-), were measured in dimethyl sulfoxide solution.The
- Zhang, Xian-Man,Bordwell, Frederick G.
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- Nucleophilic Reactivities of 2-Substituted Malonates
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Kinetics of the reactions of 2-substituted malonate anions and 5-substituted Meldrum's acid anions with benzhydrylium ions and structurally related quinone methides have been monitored in dimethyl sulfoxide solution at 20 °C. The resulting second-order rate constants followed the correlation lg k(20 °C) = sN(E + N), which allowed the nucleophile-specific parameters N and sN to be calculated for these highly stabilized carbanions and to integrate them in our comprehensive nucleophilicity scale. Given that the reactions of the benzhydrylium ions with the anions derived from 5-aryl-substituted Meldrum's acids did not proceed to completion, the corresponding equilibrium constants could be determined. In combination with available data for pyridines and benzoate ions, these equilibrium constants provide a direct comparison of the strengths of C-, N-, and O-centered Lewis bases with respect to C-centered Lewis acids.
- Puente, ángel,He, Shanshan,Corral-Bautista, Francisco,Ofial, Armin R.,Mayr, Herbert
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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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- NAMPT MODULATORS
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Provided are compounds of Formula (II) or a pharmaceutically acceptable salt thereof, wherein R1, R2, R3, R4, R5, R6, and p are as defined herein. Also provided is a pharmaceutically acceptable composition comprising a compound of Formula (II), or a pharmaceutically acceptable salt thereof. Also provided are methods of using a compound of Formula (II), or a pharmaceutically acceptable salt thereof.
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Paragraph 0218
(2021/08/13)
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- Exploration of the Synthetic Potential of Electrophilic Trifluoromethylthiolating and Difluoromethylthiolating Reagents
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The electrophilicity parameters (E) of some trifluoromethylthiolating and difluoromethylthiolating reagents were determined by following the kinetics of their reactions with a series of enamines and carbanions with known nucleophilicity parameters (N, sN), using the linear free-energy relationship log k2=sN(N+E). The electrophilic reactivities of these reagents cover a range of 17 orders of magnitude, with Shen and Lu's reagent 1 a being the most reactive and Billard's reagent 1 h being the least reactive electrophile. While the observed electrophilic reactivities (E) of the amido-derived trifluoromethylthiolating reagents correlate well with the calculated Gibbs energies for heterolytic cleavage of the X?SCF3 bonds (Tt+DA), the cumol-derived reagents 1 f and 1 g are more reactive than expected from the thermodynamics of the O?S cleavage. The E parameters of the tri/difluoromethylthiolating reagents derived in this work provide an ordering principle for their use in synthesis.
- Zhang, Jingjing,Yang, Jin-Dong,Zheng, Hanliang,Xue, Xiao-Song,Mayr, Herbert,Cheng, Jin-Pei
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supporting information
p. 12690 - 12695
(2018/09/25)
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- Method for immobilizing CuI to catalyze active methylene compound arylation by adopting fixed bed microchannel reaction device
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The invention discloses a method for immobilizing CuI to catalyze active methylene compound arylation by adopting a fixed bed microchannel reaction device. The method comprises the steps of (1) dissolving aryl halide ArX into a first organic solvent; (2) dissolving an active methylene compound, a nitrogen-oxygen polydentate ligand and organic alkali into a second organic solvent; (3) adding a solid catalyst copper iodide to a fixed bed microstructure reactor in the fixed bed microchannel reaction device; and (4) mixing the solution obtained in the step (1) and the solution obtained in the step (2) in a mixer of the microchannel reaction device, pumping the mixed solution into the fixed bed microstructure reactor obtained in the step (3), and collecting an outflow liquid after reaction. The used catalyst and ligand are low in price and easily available. Compared with the same type of reaction in the prior art, the method is short in reaction time and mild in reaction condition and has good application prospect.
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Paragraph 0046; 0047
(2017/08/29)
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- Formation of carbamates by reaction between ester carbanions and isocyanates: General regularities and scope
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General regularities and scope of reactions carbanions with the ester group at carbanionic center and arylisocyanates resulting formation of carbamates by C→N migrations of ester groups have been described. The use of tosylisocyanates terminated reactions
- Gololobov, Yuri G.,Borisov, Yuri A.,Slepchenkov, Nikolii,Barabanov, Sergey,Petrovskii, Pavel V.,Nelyubina, Julija V.
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experimental part
p. 119 - 125
(2011/07/08)
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- Novel reactions of arylmalonate carbanions. the reaction with phenyl isocyanate resulting in carbamates by 1,3-C→N migration of the ethoxycarbonyl group
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The reactions of carbanions of diethyl phenyl and 4-nitrophenylmalonates with phenyl isocyanate occur with 1,3-C→N migration of the ethoxycarbonyl group to form the corresponding adducts. The introduction of NO2 groups into the benzene ring of
- Linchenko,Krasnova,Petrovskii,Garbuzova,Khrustalev,Gololobov
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p. 1671 - 1674
(2008/09/18)
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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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- Ion channel modulating agents
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The present invention relates to ion channel modulating agents. More particularly, the present invention relates to a particular class of chemical compounds that has proven useful as modulators of SK Ca, IK Ca and BK Ca channels. In further aspects, the present invention relates to the use of these SK/IK/BK channel modulating agents for the manufacture of medicaments, for methods of therapy, and pharmaceutical compositions comprising the SK/IK/BK channel modulating agents. The SK/IK/BK channel modulating agents of the invention are useful for the treatment or alleviation of diseases and conditions associated with the SK/IK/BK channels.
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- FUSED PYRIMIDINE COMPOUNDS AND THEIR USE AS PHARMACEUTICALS
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Pharmaceutical compounds which are azolo-fused pyrimidine compounds having the formula STR1 in which =A--B--together with the pyrimidine ring forms a) a pyrazolo[1,5-a]pyrimidine of formula (A), STR2 b) a [1,2,4]triazolo[1,5-a]pyrimidine of formula (B), STR3 c) an imidazo[1,5-a]pyrimidine of formula (C), STR4 or d) an imidazo[1, 2-a]pyrimidine of formula (D), STR5
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- COPPER(I)-PROMOTED COUPLING REACTION OF ARYL HALIDES WITH SODIUM DIETHYLMALONATE
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Copper(I)-promoted coupling reaction of aryl halides with sodium diethylmalonate occured smoothly in dioxane.The qualitative trends in the activity of copper(I) salt followed the order: CuBr > CuI > CuBF4(CH3CN)4 > CuCl.The activity was lowered in the presence of coordinating molecule such as acetonitrile, pyridine, NaI, phosphine, and sulfide.The reaction was generally applicable to aryl halides with various substituents.
- Setsune, Jun-ichiro,Matsukawa, Kimihiro,Wakemoto, Hirofumi,Kitao, Teijiro
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p. 367 - 370
(2007/10/02)
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