- Bio-inspired asymmetric aldehyde arylations catalyzed by rhodium-cyclodextrin self-inclusion complexes
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Transition-metal catalysts are powerful tools for carbon-carbon bond-forming reactions that are difficult to achieve using native enzymes. Enzymes that exhibit inherent selectivities and reactivities through host-guest interactions have inspired widesprea
- Asahi, Kaoru,Fujiwara, Shin-Ichi,Iwasaki, Takanori,Kambe, Nobuaki,Takahashi, Ryota,Tsuda, Susumu,Ueda, Ryoji,Yamauchi, Hiroki
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supporting information
p. 801 - 807
(2022/02/03)
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- Electronic Effect-Guided Rational Design of Candida antarctica Lipase B for Kinetic Resolution Towards Diarylmethanols
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Herein, we developed an electronic effect-guided rational design strategy to enhance the enantioselectivity of Candida antarctica lipase B (CALB) mutants towards bulky pyridyl(phenyl)methanols. Compared to W104A mutant previously reported with reversed S-stereoselectivity toward sec-alcohols, three mutants (W104C, W104S and W104T) displayed significant improvement of S-enantioselectivity in the kinetic resolution (KR) of various phenyl pyridyl methyl acetates due to the increased electronic effects between pyridyl and polar residues. The electronic effects were also observed when mutating other residues surrounding the stereospecificity pocket of CALB, such as T42A, S47A, A281S or A281C, and can be used to manipulate the stereoselectivity. A series of bulky pyridyl(phenyl) methanols, including S-(4-chlorophenyl)(pyridin-2-yl) methanol (S-CPMA), the intermediate of bepotastine, were obtained in good yields and ee values. (Figure presented.).
- Li, Dan-Yang,Lou, Yu-Jiao,Xu, Jian,Chen, Xiao-Yang,Lin, Xian-Fu,Wu, Qi
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supporting information
p. 1867 - 1872
(2021/02/12)
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- Synthesis and biological evaluation of 1‐(Diarylmethyl)‐1h‐1,2,4‐triazoles and 1‐(diarylmethyl)‐1h‐imidazoles as a novel class of anti‐mitotic agent for activity in breast cancer
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We report the synthesis and biochemical evaluation of compounds that are designed as hybrids of the microtubule targeting benzophenone phenstatin and the aromatase inhibitor letrozole. A preliminary screening in estrogen receptor (ER)‐positive MCF‐7 breast cancer cells identified 5‐((2H‐1,2,3‐triazol‐1‐yl)(3,4,5‐trimethoxyphenyl)methyl)‐2‐methoxyphenol 24 as a potent antiproliferative compound with an IC50 value of 52 nM in MCF‐7 breast cancer cells (ER+/PR+) and 74 nM in triple‐negative MDA‐MB‐231 breast cancer cells. The compounds demonstrated significant G2/M phase cell cycle arrest and induction of apoptosis in the MCF‐7 cell line, inhibited tubulin polymerisation, and were selective for cancer cells when evaluated in non-tumorigenic MCF‐10A breast cells. The immunofluorescence staining of MCF‐7 cells confirmed that the compounds targeted tubulin and induced multinucleation, which is a recognised sign of mitotic catastrophe. Computational docking studies of compounds 19e, 21l, and 24 in the colchicine binding site of tubulin indicated potential binding conformations for the compounds. Compounds 19e and 21l were also shown to selectively inhibit aromatase. These compounds are promising candidates for development as antiproliferative, aromatase inhibitory, and microtubule‐disrupting agents for breast cancer.
- Ana, Gloria,Kelly, Patrick M.,Malebari, Azizah M.,Noorani, Sara,Nathwani, Seema M.,Twamley, Brendan,Fayne, Darren,O’boyle, Niamh M.,Zisterer, Daniela M.,Pimentel, Elisangela Flavia,Endringer, Denise Coutinho,Meegan, Mary J.
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- Reduced graphene oxide/iron oxide hybrid composite material as an efficient magnetically separable heterogeneous catalyst for transfer hydrogenation of ketones
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Reduced graphene oxide was synthesized and functionalized with FeSO4?7H2O to form a reduced graphene oxide/iron oxide hybrid composite. The hybrid composite was extensively characterized using various techniques. Its application for transfer hydrogenation of various ketones was studied. The investigation showed that it serves as a good catalyst for transfer hydrogenation of aromatic and some aliphatic ketones resulting in excellent isolated yields (97–99%) of products. It is magnetically separable showing good reusability. The products were characterized and compared with authentic ones.
- Borah, Geetika,Bordoloi, Shreemoyee,Gogoi, Pradip K.,Konwer, Surajit,Sultana, Samim
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- N-Heterocyclic Carbene (NHC)-Stabilized Ru0 Nanoparticles: In Situ Generation of an Efficient Transfer Hydrogenation Catalyst
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Tethered and untethered ruthenium half-sandwich complexes were synthesized and characterized spectroscopically. X-ray crystallographic analysis of three untethered and two tethered Ru N-heterocyclic carbene (NHC) complexes were also carried out. These RuNHC complexes catalyze transfer hydrogenation of aromatic ketones in 2-propanol under reflux, optimally in the presence of (25 mol %) KOH. Under these conditions, the formation of 2–3 nm-sized Ru0 nanoparticles was detected by TEM measurements. A solid-state NMR investigation of the nanoparticles suggested that the NHC ligands were bound to the surface of the Ru nanoparticles (NPs). This base-promoted route to NHC-stabilized ruthenium nanoparticles directly from arene-tethered ruthenium–NHC complexes and from untethered ruthenium–NHC complexes is more convenient than previously known routes to NHC-stabilized Ru nanocatalysts. Similar catalytically active RuNPs were also generated from the reaction of a mixture of [RuCl2(p-cymene)]2 and the NHC precursor with KOH in isopropanol under reflux. The transfer hydrogenation catalyzed by these NHC-stabilized RuNPs possess a high turnover number. The catalytic efficiency was significantly reduced if nanoparticles were exposed to air or allowed to aggregate and precipitate by cooling the reaction mixtures during the reaction.
- Kathuria, Lakshay,Din Reshi, Noor U.,Samuelson, Ashoka G.
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supporting information
p. 7622 - 7630
(2020/05/29)
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- A facile and highly efficient transfer hydrogenation of ketones and aldehydes catalyzed by palladium nanoparticles supported on mesoporous graphitic carbon nitride
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A novel transfer hydrogenation methodology for the reduction of ketones (14 examples) and benzaldehyde derivatives (12 examples) to the corresponding alcohols using Pd nanoparticles supported on mesoporous graphitic carbon nitride (mpg-C3N4/Pd) as a reusable catalyst and ammonia borane as a safe hydrogen source in an aqueous solution MeOH/H2O (v/v = 1/1) is described. The catalytic hydrogenation reactions were conducted in a commercially available high-pressure glass tube at room temperature, and the corresponding alcohols were obtained in high yields in 2–5 min. Moreover, the presented transfer hydrogenation protocol shows partial halogen selectivity with bromo-, fluoro-, and chloro-substituted carbonyl analogs. In addition, the present catalyst can be reused up to five times without losing its efficiency, and scaling-up the reaction enables α-methylbenzyl alcohol to be produced in 90% isolated yield.
- Ni?anc?, Bilal,Da?alan, Ziya
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- Mont-K10 Supported Fe(II) Schiff-Base Complex as an Efficient Catalyst for Hydrogenation of Ketones
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Abstract: A new Fe(II) Schiff base complex anchored on mont-K10 (Fe@imine-mont-K10) was synthesized and extensively characterized by FTIR, powder X-ray diffraction, SEM–EDX, TEM, ESR, X-ray photoelectron spectroscopy (XPS), BET surface area measurement, solid state 29Si NMR and ICP-AES analysis. The catalytic activity of the complex was investigated for hydrogenation of ketones. The results indicated that it exhibited good catalytic activity for hydrogenation of aromatic as well as aliphatic ketones in i-PrOH/CH3CN (1:1) using Na-i-OPr as base at 80?°C resulting in moderate to excellent isolated yields (51–99%) of their corresponding products. The catalyst shows good reusability. Graphical Abstract: [Figure not available: see fulltext.].
- Sultana, Samim,Borah, Geetika,Gogoi, Pradip. K.
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p. 2142 - 2157
(2019/05/28)
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- Two-component boronic acid catalysis for increased reactivity in challenging Friedel-Crafts alkylations with deactivated benzylic alcohols
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A general and efficient boronic acid catalyzed Friedel-Crafts alkylation of arenes with benzylic alcohols was previously developed for the construction of unsymmetrical diarylmethane products (X. Mo, J. Yakiwchuk, J. Dansereau, J. A. McCubbin and D. G. Hall, J. Am. Chem. Soc., 2015, 137, 9694). Highly electron-deficient benzylic alcohols, however, were ineffective coupling partners due to the increased difficulty of C-O bond ionization. Herein, we report the use of perfluoropinacol as an effective co-catalyst to improve the reactivity of a boronic acid catalyst in the Friedel-Crafts benzylations of electronically deactivated primary and secondary benzylic alcohols. According to spectroscopic studies, it is believed that perfluoropinacol condenses with the arylboronic acid catalyst to form a highly electrophilic and Lewis acidic boronic ester. This in situ formed species enables a more facile ionization of the benzylic alcohols likely through a mode of activation promoted by a Lewis acid assisted hydronium Br?nsted acid generated from the interactions of the transient boronic ester with hexafluoroisopropanol solvent and water.
- Ang, Hwee Ting,Rygus, Jason P. G.,Hall, Dennis G.
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supporting information
p. 6007 - 6014
(2019/06/24)
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- β-Amino Phosphine Mn Catalysts for 1,4-Transfer Hydrogenation of Chalcones and Allylic Alcohol Isomerization
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Mn complexes with amino acid derived PN ligands were used in the catalytic transfer hydrogenation (TH) of ketone and chalcone substrates in 2-propanol with mild heating. Moreover, chalcones are reduced selectively to the saturated ketone at short times and can be fully converted to the alcohol when reactions are prolonged. The mechanism of chalcone reduction was briefly considered. Allylic alcohols are not reactive in 2-propanol, but quantitative isomerization occurs in toluene. Thus, we suspect that the allylic alcohols are dehydrogenated and the resulting ketone is formed through a direct 1,4-hydrogenation of the chalcone. Finally, several other related ligands that have been used in Mn-based TH reactions were explored to test the viability of ligand design in favoring chemoselectivity. The β-amino phosphine ligands proved most effective in this regard.
- Vigneswaran, Vipulan,MacMillan, Samantha N.,Lacy, David C.
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supporting information
p. 4387 - 4391
(2019/11/14)
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- Carbohydrate-functionalized N-heterocyclic carbene Ru(ii) complexes: Synthesis, characterization and catalytic transfer hydrogenation activity
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Three Ru complexes containing carbohydrate/N-heterocyclic carbene hybrid ligands were synthesized that were comprised of a triazolylidene coordination site and a directly linked per-acetylated glucosyl (5Glc) or galactosyl unit (5Gal), or a glycosyl unit linked through an ethylene spacer (6). Electrochemical and UV-vis analysis indicate only minor perturbation of the electronic configuration of the metal center upon carbohydrate installation. Deprotection of the carbohydrate was accomplished under basic conditions to afford complexes that were stable in solution over several hours, but decomposed in the solid state. Complexes 5 and 6 were used as pre-catalysts for transfer hydrogenation of ketones under basic conditions, i.e. conditions that lead to in situ deprotection of the carbohydrate entity. The carbohydrate directly influences the catalytic activity of the metal center. Remotely linked carbohydrates (complex 6) induce significantly lower catalytic activity than directly linked carbohydrates (complexes 5Glc, 5Gal), while unfunctionalized triazolylidenes are an order of magnitude more active. These observations and substrate variations strongly suggest that substrate bonding is rate-limiting for transfer hydrogenation in these hybrid carbohydrate/triazolylidene systems.
- Byrne, Joseph P.,Musembi, Pauline,Albrecht, Martin
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p. 11838 - 11847
(2019/08/13)
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- Nickel Catalyzed Intermolecular Carbonyl Addition of Aryl Halide
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In this study, we develop a nickel-catalyzed carbonyl arylation reaction employing aldehydes with aryl and allyl halides. Various aryl, α,β-unsaturated aldehyde and aliphatic aldehydes can be converted into their corresponding secondary alcohols in moderate-to-high yields. In addition, we extended this approach to develop an asymmetric reductive coupling reaction that combines nickel salts with chiral bisoxazoline ligands to give secondary alcohols with moderate enantioselectivity.
- Ishida, Seima,Suzuki, Hiroyuki,Uchida, Seiichiro,Yamaguchi, Eiji,Itoh, Akichika
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supporting information
p. 7483 - 7487
(2019/12/11)
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- Carbenium ion formation by fragmentation of electrochemically generated oxonium ions
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Fragmentation of electrochemically generated oxonium ions can be exploited to form carbenium ions at a low oxidation potential in the presence of a nucleophile. The application of this concept is demonstrated for the allylation of carbenium ions generated by the anodic oxidation of stannylmethylethers.
- Lielpetere, Anna,Jirgensons, Aigars
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supporting information
p. 5094 - 5096
(2018/07/29)
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- Chemoselective transfer hydrogenation of nitroarenes, ketones and aldehydes using acylthiourea based Ru(II)(p-cymene) complexes as precatalysts
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A new series of Ru(II)(η6-p-cymene) complexes (1–5) was synthesized from pyridine based acylthiourea ligands (L1-L5) and [Ru(η6-p-cymene)Cl2]2. All the ligands and complexes were well characterized by UV-Visible, FT-IR, mass and 1H & 13C NMR spectroscopic techniques. The molecular structures of the ligands (L1, L2, L4 and L5) and complex 1 were confirmed using single crystal X-ray diffraction study. The Ru(II)(η6-p-cymene) complexes (1–5) were proved to be efficient precatalysts for the transfer hydrogenation of carbonyl compounds and nitroarenes in the presence of 2-propanol as a hydrogen donor and KOH as a base. The catalytic transfer hydrogenation reactions were chemoselective towards the nitro group in presence of carbonyl group, which is a rare scenario in homogeneous catalysis. The catalyst was compatible with broad range of substrates which include furfural, quinone and many heterocycles. The catalytic reactions exhibited very high conversions (upto 100%) and excellent yields (upto 99%). Turn Over Number (TON) was found upto 990.
- Sathishkumar, Pushpanathan N.,Raveendran, Neethi,Bhuvanesh, Nattamai S.P.,Karvembu, Ramasamy
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- Employing Arynes for the Generation of Aryl Anion Equivalents and Subsequent Reaction with Aldehydes
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Arynes are highly reactive intermediates, which are utilized for the electrophilic arylation of various X-H bonds (X = O, N, S etc.). Herein, a new synthetic strategy is demonstrated, where arynes are converted into aryl anion equivalents by treatment with phosphines and a base. The addition of phosphines to arynes form the phosphonium salts, which in the presence of a carbonate base generates the aryl anion equivalent. Subsequent addition of the aryl anions with aldehydes afforded the secondary alcohols.
- Gaykar, Rahul N.,Bhunia, Anup,Biju, Akkattu T.
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p. 11333 - 11340
(2018/07/21)
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- Bench-Stable Sulfoxide-Based Boronates: Preparation and Application in a Tandem Suzuki Reaction
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A set of novel aromatic and heteroaromatic bench-stable sulfoxide-based boronates was prepared. The structure of the boronates was established by means of X-ray crystallography, and the prepared boronates were successively used in Suzuki cross-coupling reactions under different conditions. We also developed a tandem Suzuki reaction so that a base is generated during the nucleophilic addition of Grignard reagents to 4-bromobenzaldehyde. The formed intermediates were smoothly coupled with the prepared boronates and the boronic acids under external base-free conditions. (Figure presented.).
- ?ubiňák, Marek,Eigner, Václav,Tobrman, Tomá?
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p. 4604 - 4614
(2018/10/31)
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- Synthesis of Allocolchicine Conjugates with a Cetirizine Analog
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Conjugates of allocolchicine and a cetirizine analog have been synthesized as potential anti-inflammatory and anti-allergic drugs.
- Zotov,Shchegravina,Fedorov, A. Yu.
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p. 1498 - 1504
(2019/01/04)
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- [Ir(COD)Cl]2/tris(2,4-di-t-butylphenyl)phosphite-catalyzed addition reactions of arylboronic acids with aldehydes
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[Ir(COD)Cl]2/tris(2,4-di-t-butylphenyl)phosphite-catalyzed addition reactions of arylboronic acids with aldehydes were described. The Ir(I) catalyst, generated from [Ir(COD)Cl]2 and tris(2,4-di-t-butylphenyl)phosphite, was an efficient catalyst system for the addition reactions of a variety of arylboronic acids with aromatic and aliphatic aldehydes. The easy availability of the catalyst and good yields make these reactions potentially useful in organic synthesis.
- Liao, Yuan-Xi,Dong, Jie,Hu, Qiao-Sheng
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supporting information
p. 1548 - 1550
(2018/03/26)
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- An Efficient Ga(OTf)3/Isopropanol Catalytic System for Direct Reduction of Benzylic Alcohols
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This study aims to report the first gallium-catalyzed direct reduction of benzylic alcohols using isopropanol as a reductant. The reaction proceeds via gallium catalyst-assisted hydride transfer of the in situ-generated benzylic isopropyl ether. The method generates only water and acetone as byproducts and thus provides an atom-economic and environmentally friendly approach to the synthesis of di- and triarylmethanes, which are important substructures in various bioactive compounds and functional materials. (Figure presented.).
- Sai, Masahiro
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supporting information
p. 4330 - 4335
(2018/10/15)
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- Aryl appended neutral and cationic half-sandwich ruthenium(II)-NHC complexes: Synthesis, characterisation and catalytic applications
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Half-sandwich ruthenium(ii) complexes 1-6 bearing imidazolylidene and pyridyl-imidazolylidene ligands have been synthesised in good yields and were characterised on the basis of spectral and analytical evidence. In addition, the structures of the complexes 1-4 were unambiguously established through single crystal X-ray analysis. Transmetalation of the ligands followed by complexation with ruthenium precursors yielded the air and moisture stable complexes. The crystal structures of these complexes exhibited piano-stool geometries with η6-coordination of the p-cymene or hexamethylbenzene moieties. These complexes exhibited catalytic activity in the transfer hydrogenation of carbonyls in an alkaline medium using 2-propanol as the hydrogen source. The effect of variations in the catalyst structure on the transfer hydrogenation and stability was investigated in detail, and theoretical calculations were employed to understand the mechanism of the catalytic activity. The neutral ruthenium-NHC complexes 1 and 2 showed the efficiency of ca. 100% at a catalyst loading of ca. 2 mol% within 2 h of the reaction in 2-propanol, whereas quantitative yields were obtained in the presence of cationic ruthenium-NHC complexes 3-6 within 1 h at a low catalyst loading of ca. 0.5 mol%, thereby demonstrating their robustness for the transfer hydrogenation of the aromatic ketones.
- Viji, Mambattakkara,Tyagi, Nidhi,Naithani, Neeraj,Ramaiah, Danaboyina
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supporting information
p. 12736 - 12745
(2017/11/06)
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- Stoichiometric and Catalytic C?C and C?H Bond Formation with B(C6F5)3 via Cationic Intermediates
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This work showcases a new catalytic cyclization reaction using a highly Lewis acidic borane with concomitant C?H or C?C bond formation. The activation of alkyne-containing substrates with B(C6F5)3 enabled the first catalytic intramolecular cyclizations of carboxylic acid substrates using this Lewis acid. In addition, intramolecular cyclizations of esters enable C?C bond formation as catalytic B(C6F5)3 can be used to effect formal 1,5-alkyl migrations from the ester functional groups to unsaturated carbon–carbon frameworks. This metal-free method was used for the catalytic formation of complex dihydropyrones and isocoumarins in very good yields under relatively mild conditions with excellent atom efficiency.
- Soltani, Yashar,Wilkins, Lewis C.,Melen, Rebecca L.
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supporting information
p. 11995 - 11999
(2017/09/20)
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- AlCl3 catalyzed coupling of: N-benzylic sulfonamides with 2-substituted cyanoacetates through carbon-nitrogen bond cleavage
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A new cross-coupling reaction of N-benzylic sulfonamides with 2-substituted cyanoacetates for the synthesis of 2-substituted benzylbenzene was reported. In the presence of AlCl3, a broad range of N-benzylic sulfonamides reacted smoothly with 2-substituted cyanoacetates to afford structurally diverse benzylbenzenes in moderate to excellent yields. The conversion could be enlarged to gram-scale efficiently. The practicability of this approach was further manifested in the synthesis of a related bioactive agent with high anti-inflammatory activity.
- Hu, Chen,Hong, Gang,Qian, Xiaofei,Kim, Kwang Rim,Zhu, Xiaoyan,Wang, Limin
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supporting information
p. 4984 - 4991
(2017/07/10)
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- The Asymmetric Piers Hydrosilylation
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An axially chiral, cyclic borane decorated with just one C6F5 group at the boron atom promotes the highly enantioselective hydrosilylation of acetophenone derivatives without assistance of an additional Lewis base (up to 99% ee). The reaction is an unprecedented asymmetric variant of Piers' B(C6F5)3-catalyzed carbonyl hydrosilylation. The steric congestion imparted by the 3,3′-disubstituted binaphthyl backbone of the borane catalyst as well as the use of reactive trihydrosilanes as reducing agents are keys to success.
- Süsse, Lars,Hermeke, Julia,Oestreich, Martin
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supporting information
p. 6940 - 6943
(2016/07/06)
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- Synthesis and Anticancer Activity of 1-(1H -Indol-3-yl)-2-(4-diarylmethylpiperazine-1-yl)ethane-1,2-dione Derivatives
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Several new 1-(4-diarylmethylpiperazine-1-yl)-2-(1H-indol-3-yl)ethane-1,2-dione derivatives were synthesized by acylation of 1-diarylmethylpiperazine with 2-(1H-indol-3-yl)-2-oxoacetyl chloride. Their structures were confirmed by 1H NMR, IR, mass spectra, and elemental analysis. These compounds were further evaluated for their anticancer activity, and most of them were found to have moderate-to-potent antiproliferative activities against Hela, A-549, and ECA-109 cancer cell lines in vitro.
- Jiang, Jun-Rong,Xu, Feng,Wu, Han-Gui
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- Boron Trifluoride?Diethyl Ether-Catalyzed Etherification of Alcohols: A Metal-Free Pathway to Diphenylmethyl Ethers
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A novel boron trifluoride?diethyl ether (BF3?OEt2)-catalyzed etherification procedure has been developed in which primary and secondary alcohols are easily converted into diphenylmethyl ethers with yields of up to 99%.
- Li, Jiaqiang,Zhang, Xiaohui,Shen, Hang,Liu, Qing,Pan, Jing,Hu, Wen,Xiong, Yan,Chen, Changguo
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supporting information
p. 3115 - 3120
(2015/11/03)
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- Discovery of 1,1′-Biphenyl-4-sulfonamides as a New Class of Potent and Selective Carbonic Anhydrase XIV Inhibitors
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New 1,1′-biphenylsulfonamides were synthesized and evaluated as inhibitors of the ubiquitous human carbonic anhydrase isoforms I, II, IX, XII, and XIV using acetazolamide (AAZ) as reference compound. The sulfonamides 1-21 inhibited all the isoforms, with Ki values in the nanomolar range of concentration, and were superior to AAZ against all of them. X-ray crystallography and molecular modeling studies on the adducts that compound 20, the most potent hCA XIV inhibitor of the series (Ki = 0.26 nM), formed with the five hCAs, provided insight into the molecular determinants responsible for the high affinity of this molecule toward the target enzymes. The results pave the way to the development of 1.1′-biphenylsulfonamides as a new class of highy potent hCA XIV inhibitors.
- La Regina, Giuseppe,Coluccia, Antonio,Famiglini, Valeria,Pelliccia, Sveva,Monti, Ludovica,Vullo, Daniela,Nuti, Elisa,Alterio, Vincenzo,De Simone, Giuseppina,Monti, Simona Maria,Pan, Peiwen,Parkkila, Seppo,Supuran, Claudiu T.,Rossello, Armando,Silvestri, Romano
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supporting information
p. 8564 - 8572
(2015/11/24)
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- Triply cyclometalated trinuclear iridium(iii) and trinuclear palladium(ii) complexes with a tri-mesoionic carbene ligand
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The first example of a triply cyclometalated homopolynuclear tri-IrIII complex with additional carbene donors is presented. Cooperative catalysis and the interplay between homogenous and heterogeneous catalyses are discussed for the tri-IrIII complex and a related non-cyclometalated tri-PdII complex.
- Maity, Ramananda,Mekic, Amel,Van Der Meer, Margarethe,Verma, Amit,Sarkar, Biprajit
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supporting information
p. 15106 - 15109
(2015/10/12)
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- The carbonyl group tuned electron-deficient phosphorus ligands and their application in Rhodium catalyzed arylation to aldehydes
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Acylphosphines, which could be efficiently prepared from acid chlorides and secondary phosphines, were developed as a type of carbonyl group tuned electron-deficient phosphorus ligand. They were found to be a kind of efficient ligand in Rhodium catalyzed arylation to aldehydes through accelerating the transmetalation process. Chiral acylphosphine ligands could be generated from carboxylic acids bearing the chiral framework correspondingly.
- Yang, Jiefang,Chen, Xingyu,Wang, Zhiqian
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supporting information
p. 5673 - 5675
(2015/09/15)
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- Highly efficient homogeneous and heterogenized ruthenium catalysts for transfer hydrogenation of carbonyl compounds
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[Ru(acac)2(CH3CN)2] was synthesized from [Ru(acac)3] by refluxing it with zinc powder in ethanol-acetonitrile mixture. The prepared catalyst was characterized by FT-IR, 1H and 13C NMR techniques. The silica supported catalyst ('SiO 2'-NH2-RuII) was prepared by stirring [Ru(acac)2(CH3CN)2] with 'SiO 2'-NH2 in a 1:1 mixture of CH2Cl 2-toluene for 3 days at room temperature. It was characterized by FT-IR, SEM, solid state NMR, ICP and BET surface area methods. The transfer hydrogenation reaction of carbonyl compounds was carried out separately using [Ru(acac)2(CH3CN)2] and 'SiO 2'-NH2-RuII as catalysts. The reaction conditions were optimized with different solvents, bases, catalyst amounts and temperatures using acetophenone as a model system. The scope of the reaction was extended to various substituted aryl ketones including heteroaryl ketones. This journal is the Partner Organisations 2014.
- Ganesamoorthy,Jerome,Shanmugasundaram,Karvembu
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p. 27955 - 27962
(2014/07/21)
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- Palladium-catalyzed arylation of aldehydes with bromo-substituted 1,3-diaryl-imidazoline carbene ligand
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The combination of 0 valent palladium precursor and bromo-substituted 1,3-diaryl-imidazoline carbene ligand precursor such as 1-(2-bromophenyl)-3-(2,6-diisopropylphenyl)-imidazolinium chloride 1a exhibited high catalytic activity for the 1,2-addition of arylboronic acids to aldehydes including aqueous formaldehyde.
- Yamamoto, Tetsuya,Furusawa, Takuma,Zhumagazin, Azamat,Yamakawa, Tetsu,Oe, Yohei,Ohta, Tetsuo
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- Bu4N+ alkoxide-initiated/autocatalytic addition reactions with organotrimethylsilanes
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The use of Me3SiO-/Bu4N+ as a general activator of organotrimethylsilanes for addition reactions has been established. The broad scope of the method offers trimethylsilanes (including acetate, allyl, propargyl, benzyl, dithiane, heteroaryl, and aryl derivatives) as bench-stable organometallics that can be readily utilized as carbanion equivalents for synthesis. Reactions are achieved at rt without the requirement of specialized precautions that are commonplace for other organometallics.
- Das, Manas,O'Shea, Donal F.
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p. 5595 - 5607
(2014/07/08)
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- Lewis base activation of Lewis acids: Group 13. in situ generation and reaction of borenium ions
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A variety of Lewis bases were combined with 9-BBN-NTf2 to establish the requirements for the generation of borenium cations. Five different types of behaviors were found, but the most interesting was the combination of Et3N, DABCO, 2,6-lutidine, or Ph3P=S, which formed borenium ions exclusively even in sub- or superstoichiometric quantities. The 9-BBN borenium ion complex of 2,6-lutidine rapidly catalyzes the hydrosilylation of a variety of ketones in the presence of Et3SiH. Preliminary mechanistic experiments suggest that the reduction involves borenium ion activation of Et3SiH and not the ketone.
- Denmark, Scott E.,Ueki, Yusuke
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supporting information
p. 6631 - 6634
(2014/01/06)
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- Retention or inversion in stereospecific nickel-catalyzed cross-coupling of benzylic carbamates with arylboronic esters: Control of absolute stereochemistry with an achiral catalyst
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Stereospecific coupling of benzylic carbamates and pivalates with aryl- and heteroarylboronic esters has been developed. The reaction proceeds with selective inversion or retention at the electrophilic carbon, depending on the nature of the ligand. Tricyclohexylphosphine ligand provides the product with retention, while an N-heterocyclic carbene ligand provides the product with inversion.
- Harris, Michael R.,Hanna, Luke E.,Greene, Margaret A.,Moore, Curtis E.,Jarvo, Elizabeth R.
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supporting information
p. 3303 - 3306
(2013/04/10)
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- LYSOPHOSPHATIDIC ACID RECEPTOR ANTAGONISTS
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Compounds, methods of making such compounds, pharmaceutical compositions and medicaments comprising such compounds, and methods of using such compounds to treat, prevent or diagnose diseases, disorders, or conditions associated with one or more of the lysophosphatidic acid receptors are provided.
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Paragraph 0425
(2013/03/26)
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- Direct electrosynthesis of ketones from benzylic methylenes by electrooxidative C-H activation
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Electrify your chemistry! Direct electrosynthesis of ketones from benzylic methylenes in an undivided cell was realized in moderate to good yields (see scheme). In this electrosynthesis, electrons instead of conventional oxidants and catalysts are employed to make the reaction environmentally benign. Moreover, the reaction intermediate radical was detected by ESR spectroscopy and the reaction mechanism was clarified.
- Meng, Li,Su, Jihu,Zha, Zhenggen,Zhang, Li,Zhang, Zhenlei,Wang, Zhiyong
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supporting information
p. 5542 - 5545
(2013/05/23)
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- Effects of phosphorus substituents on reactions of α- alkoxyphosphonium salts with nucleophiles
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The effects of phosphorus substituents on the reactivity of α-alkoxyphosphonium salts with nucleophiles has been explored. Reactions of α-alkoxyphosphonium salts, prepared from various acetals and tris(o-tolyl)phosphine, with a variety of nucleophiles proceeded efficiently. These processes represent the first examples of high-yielding nucleophilic substitution reactions of α-alkoxyphosphonium salts. The reactivity of these salts was determined by a balance between steric and electronic factors, respectively, represented by cone angles θ and CO stretching frequencies ν (steric and electronic parameters, respectively). In addition, a novel reaction of α-alkoxyphosphonium salts derived from Ph3P with Grignard reagents was observed to take place in the presence of O2 to afford alcohols in good yields. A radical mechanism is proposed for this process that has gained support from isotope-labeling and radical-inhibition experiments. A dramatic change in the reactivity of an α-alkoxyphosphonium salt toward nucleophiles is observed due to the steric and electronic nature of the phosphine substituents. By changing the type of phosphorus substituents, the reaction pathway can be controlled to proceed selectively by substitution or a new radical reaction (see scheme; OTf=trifluoromethansulfonate, TMS=trimethylsilyl, o-tol=tolyl). Copyright
- Goto, Akihiro,Otake, Kazuki,Kubo, Ozora,Sawama, Yoshinari,Maegawa, Tomohiro,Fujioka, Hiromichi
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p. 11423 - 11432
(2012/11/07)
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- METHOD FOR SYNTHESIS OF SECONDARY ALCOHOLS
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A method for synthesis of secondary alcohols is provided for pharmaceutical secondary alcohol by addition of organoboronic acids with aldehydes in presence of the cobalt ion and bidentate ligands as the catalyst. In addition, an enantioselective synthesis method for secondary alcohols is also herein provided in the present invention. The present invention has advantages in using less expensive cobalt ion and commercially available chiral ligands as the catalyst, wide scope of organoboronic acids and aldehydes compatible with this catalytic reaction and achieving excellent yields and/or enantiomeric excess.
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Page/Page column 2
(2012/06/16)
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- Vanadium-catalyzed atmosphericoxidation of benzyl alcoholsusing water as Solvent
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A vanadium complex combined with 4,4'-di-tert-butyl-2,2'- bipyridyl as a ligand exhibited excellent catalytic activity in atmosphericoxidation of benzhydrolsusing water as solvent to afford benzophenones in good yields.
- Kodama, Shintaro,Hashidate, Suguru,Nomoto, Akihiro,Yano, Shigenobu,Ueshima, Michio,Ogawa, Akiya
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supporting information; experimental part
p. 495 - 497
(2011/08/05)
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- N-heterocyclic carbene-catalyzed cross-coupling of aromatic aldehydes with activated alkyl halides
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N-Heterocyclic carbene-catalyzed umpolung of aldehydes followed by their interception with diarylbromomethanes has been reported. This conceptually novel transition-metal-free cross-coupling of aldehydes with alkyl halides works well at low catalyst loadings and under mild reaction conditions leading to the formation of diaryl acetophenone derivatives in good yields. In addition, α-halo ketones and esters can also be used as aldehyde reaction partners.
- Padmanaban, Mohan,Biju, Akkattu T.,Glorius, Frank
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supporting information; experimental part
p. 98 - 101
(2011/03/19)
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- An unusual reaction of α-alkoxyphosphonium salts with Grignard reagents under an O2 atmosphere
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An unusual and novel reaction of α-alkoxyphosphonium salts, generated from O,O-acetals and Ph3P, with Grignard reagents under an O 2 atmosphere afforded alcohols in moderate to high yields. It was clarified by isotopic labelling experiments that the reaction proceeded via a novel radical pathway.
- Fujioka, Hiromichi,Goto, Akihiro,Otake, Kazuki,Kubo, Ozora,Sawama, Yoshinari,Maegawa, Tomohiro
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p. 9894 - 9896
(2011/10/09)
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- A nontransmetalation reaction pathway for anionic four-electron donor-based palladacycle-catalyzed addition reactions of arylborons with aldehydes
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A nontransmetalation reaction pathway for anionic four-electron donor-based (Type I) palladacycle-catalyzed addition reactions of arylborons with aldehydes is described. This new reaction pathway offers new catalysis opportunities for Type I palladacycle-catalyzed addition reactions such as the exceptionally low catalyst loading catalysis, with the catalyst loading as low as 0.0005 mol %. This new pathway may be applicable for other transition metal-catalyzed addition reactions and might lead to the development of new reactions including sequential/tandem reactions.
- Liao, Yuan-Xi,Xing, Chun-Hui,Israel, Matthew,Hu, Qiao-Sheng
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supporting information; experimental part
p. 3324 - 3328
(2011/06/28)
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- A simple procedure for the polymer-supported N-heterocyclic carbene-rhodium complex via click chemistry: A recyclable catalyst for the addition of arylboronic acids to aldehydes
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A novel polymer-supported carbene-rhodium complex was prepared using a simple procedure via click chemistry. This polymer-supported N-heterocyclic carbene-rhodium complex was characterized and used as a catalyst for the addition of arylboronic acids to aldehydes in good to excellent yields.
- He, Ying,Cai, Chun
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supporting information; experimental part
p. 12319 - 12321
(2011/12/15)
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- Microwave-assisted nickel(II) acetylacetonate-catalyzed arylation of aldehydes with arylboronic acids
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Applying sealed vessel microwave heating at 180 °C in toluene the arylation of aromatic and aliphatic aldehydes with arylboronic acids using 1-2 mol % of Ni(acac)2 as a catalyst can be performed efficiently within 10-30 min providing the desired diarylmethanols or benzyl alcohols in good yields.
- Chen, Wen,Baghbanzadeh, Mostafa,Kappe, C. Oliver
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experimental part
p. 1677 - 1679
(2011/04/25)
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- Synthesis and anticonvulsant activity of some cinnamylpiperazine derivatives
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A series of cinnamylpiperazine derivatives was synthesized using different benzophenone as starting material. The structures of the compounds were proved by their IR, 1H-NMR spectroscopic data and mass spectra data. The anticonvulsant activities of these compounds were evaluated with maximal electroshock (MES) test and rotarod test with intraperitoneal injection on KunMing mice. Among all the flunarizine analogues, no one exhibited better anticonvulsant activity than flunarizine. Flunarizine (4i) exhibited anticonvulsant activity with ED50 of 38.1 mg/kg, TD50 of 164.3 mg/kg and PI of 4.3 through administration intraperitoneal, and with ED50 of 56.8 mg/kg, TD50 of 456.3 mg/kg and PI of 8.0 through oral administration.
- Hu, Chuan,Sun, Zhi-Gang,Wei, Cheng-Xi,Quan, Zhe-Shan
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scheme or table
p. 661 - 664
(2011/11/29)
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- Palladium-imidazolinium carbene-catalyzed arylation of aldehydes with arylboronic acids in water
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The catalytic arylation of aldehydes with arylboronic acids in only water was found to be achieved using the palladium/thioether-imidazolinium chloride system in good to excellent yields. This catalytic process showed high tolerance for a broad range of substrates, giving a variety of carbinol derivatives with 2.0-3.0 mol % of the catalyst.
- Kuriyama, Masami,Ishiyama, Natsuki,Shimazawa, Rumiko,Onomura, Osamu
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experimental part
p. 6814 - 6819
(2010/10/02)
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- Discovery of novel and potent benzhydryl-tropane trypanocides highly selective for Trypanosoma cruzi
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A benzhydryl tropinone oxime that is potently toxic to Trypanosoma cruzi has been previously identified. An SAR investigation determined that no part of the original compound was superfluous and all early SAR probes led to significant drops in activity. The only alteration that could be achieved without loss of activity was replacement of the aryl chloride substituent with chloro homologues. This led to the discovery of a trifluoromethyl-containing analogue with an EC50 against T. cruzi of 30 nM and a cytotoxicity selectivity index of over 1000 relative to rat skeletal myoblast L-6 cells.
- Holloway,Parisot,Novello,Watson,Armstrong,Thompson,Street,Baell
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supporting information; experimental part
p. 1816 - 1818
(2010/06/21)
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- Rhodium-catalyzed 1,2-addition of Sb-phenyl-1,5-azastibocines to functionalized aldehydes
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Simple and efficient addition of a phenyl group to aldehydes was accomplished by the rhodium-catalyzed reaction of Sb-phenyl-1,5-azastibocines. Because of the soft nucleophilic character of 1,5-azastibocines, arylation of functionalized aldehydes having ketone, ester, and halogen moieties can be achieved to afford aryl alcohols. The reaction can be carried out under aerobic conditions, in striking contrast to the reactions with hard nucleophiles such as organolithium and Grignard reagents.
- Kakusawa, Naoki,Yasuike, Shuji,Kurita, Jyoji
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experimental part
p. 163 - 168
(2010/04/29)
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- Ni(COD)2/4-ClC6H4COR-catalyzed addition reactions of arylboroxines with aldehydes
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Ni(COD)2/4-ClC6H4COR (R = H, CH3, Ph) was found to be an efficient catalyst system for the addition reactions of arylboroxines with aromatic and aliphatic aldehydes. The catalytically active species for Ni(COD)2/4-ClC6H4COR catalyst systems was likely to be their oxidative addition adducts, 4-RCOC6H4Ni(II)Cl(COD) complexes.
- Xing, Chun-Hui,Hu, Qiao-Sheng
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supporting information; experimental part
p. 924 - 927
(2010/05/18)
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- Cobalt-catalyzed addition reaction of organoboronic acids with aldehydes: Highly enantioselective synthesis of diarylmethanols
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Predicted outcomes: The addition reaction of organoboronic acids with aldehydes in the presence of K2CO3 catalyzed by CoI 2/ACHTUNGRE(R,R)-BDPP gives chiral secondary alcohols in excellent yields with 90-99 % enantiomeric excess (see scheme; (R,R)-BDPP = (2R,4R)-(+)-2,4-bis(diphenyl-phosphino)pentane). This method provides an alternative to prepare an R and S enantiomeric pair by using the same chiral ligand and allows the stereochemical outcome of the reaction to be predicted.
- Karthikeyan, Jaganathan,Jeganmohan, Masilamani,Cheng, Chien-Hong
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supporting information; experimental part
p. 8989 - 8992
(2010/10/02)
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- An efficient and transition metal free protocol for the transfer hydrogenation of ketones as a continuous flow process
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We report the efficient reduction of a selection of ketones to the corresponding secondary alcohols using only catalytic amounts of LiOtBu in iPrOH facilitated by using a continuous flow reactor.
- Sedelmeier, Joerg,Ley, Steven V.,Baxendale, Ian R.
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experimental part
p. 683 - 685
(2010/04/23)
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- A metal-free catalytic system for the oxidation of benzylic methylenes and primary amines under solvent-free conditions
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Iodine-pyridine-tert-butylhydroperoxide is developed as a green and efficient catalytic system for the oxidation of benzylic methylenes to ketones and primary amines to nitriles. The reaction conditions are quite mild and environmentally benign, no transition metals, organic solvents or hazard reagents being needed. The oxidation of benzylic methylenes gave the corresponding ketones in excellent yields with complete chemoselectivity, while the oxidation of primary amines was complete in several minutes, affording various nitriles in moderate to good yields.
- Zhang, Jintang,Wang, Zhentao,Wang, Ye,Wan, Changfeng,Zheng, Xiaoqi,Wang, Zhiyong
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supporting information; scheme or table
p. 1973 - 1978
(2010/06/15)
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