- One-pot synthesis of new chiral sulfides and selenides containing oxazolidines: Catalyst in the enantioselective addition of diethylzinc to benzaldehyde
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A new easily accessible class of chiral sulfides 1 and selenides 2 containing oxazolidine was prepared from amino acids. They were used as chiral ligands in the catalytic asymmetric addition of diethylzinc to benzaldehyde to give the corresponding seconda
- Braga, Antonio L.,Rodrigues, Oscar E. D.,Paixao, Marcio W.,Appelt, Helmoz R.,Silveira, Claudio C.,Bottega, Diana P.
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- Quantitative Profiling of Protein Carbonylations in Ferroptosis by an Aniline-Derived Probe
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Ferroptosis is a regulated form of necrotic cell death implicated in carcinogenesis and neurodegeneration that is driven by phospholipid peroxidation. Lipid-derived electrophiles (LDEs) generated during this process can covalently modify proteins ("carbonylation") and affect their functions. Here we report the development of a quantitative chemoproteomic method to profile carbonylations in ferroptosis by an aniline-derived probe. Using the method, we established a global portrait of protein carbonylations in ferroptosis with >400 endogenously modified proteins and for the first time, identified >20 residue sites with endogenous LDE modifications in ferroptotic cells. Specifically, we discovered and validated a novel cysteine site of modification on voltage-dependent anion-selective channel protein 2 (VDAC2) that might play an important role in sensitizing LDE signals and mediating ferroptosis. Our results will contribute to the understanding of ferroptotic signaling and pathogenesis and provide potential biomarkers for ferroptosis detection.
- Chen, Ying,Liu, Yuan,Lan, Tong,Qin, Wei,Zhu, Yuntao,Qin, Ke,Gao, Jinjun,Wang, Haobo,Hou, Xiaomeng,Chen, Nan,Friedmann Angeli, Jose Pedro,Conrad, Marcus,Wang, Chu
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- Synthesis of tubuvaline (Tuv) fragment of tubulysin via diastereoselective dihydroxylation of homoallylamine
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Tubulysins are natural anticancer molecules that directly bind and inhibit tubulin polymerization in actively dividing cells leading to apoptosis and cell death. Structurally, tubulysins are linear tetrapeptides, constituted by a natural amino acid (Ile)
- Reddy, Ramesh B.,M, Vijay,Krishnan, Mena Asha,Chelvam, Venkatesh
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- Enantioselective Synthesis of α-Functionally Substituted Cyclic Ketones via Chiral Organotin Enamines
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Chiral organotin enamines 1a-f are easily prepared from cyclic ketones, chiral amino alcohols 5a-c (derived from amino acids), and an organotin precursor.Nucleophilic addition of these compounds to electrophilic alkenes followed by hydrolysis leads to the
- Stetin, Cecile,Jeso, Bernard De,Pommier, Jean-Claude
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- Synthesis and properties of ionic liquids derived from the 'chiral pool'
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New chiral ionic liquids have been synthesised which are directly derived from the 'chiral pool' and therefore readily available in kg scale; NMR-measurements indicate that these liquids may be interesting solvents for enantioselective reactions and useful in chiral separation techniques.
- Wasserscheid, Peter,Boesmann, Andreas,Bolm, Carsten
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- Synthesis and characterization of chiral ionic liquids based on quinine, L-proline and L-valine for enantiomeric recognition
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The separation of enantiomers remains a major challenge for the pharmaceutical industry. In this work, eight chiral ionic liquids (CILs) directly derived from the ‘chiral pool’ were synthesized and characterized in order to develop enantioselective systems, for the chiral resolution. According to their chiral cations, three different groups of CILs were prepared, namely based on quinine, L-proline and L-valine, and their enantiomeric recognition ability evaluated. For that purpose the diastereomeric interactions between a racemic mixture of Mosher's acid sodium salt and each CIL were studied using 19F NMR spectroscopy. The remarkable chemical shift dispersion induced by some CILs demonstrates their potential application in chiral resolution. Additionally the optical rotation, thermophysical properties and ecotoxicity against the marine bacteria Aliivibrio fischeri of these chiral ionic liquids were addressed.
- Sintra, Tania E.,Gantman, Mikhail G.,Ventura, Sónia P.M.,Coutinho, Jo?o A.P.,Wasserscheid, Peter,Schulz, Peter S.
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- Immobilization of (l)-valine and (l)-valinol on SBA-15 nanoporous silica and their application as chiral heterogeneous ligands in the Cu-catalyzed asymmetric allylic oxidation of alkenes
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SBA-15 nanoporous silica was synthesized by hydrothermal method using P123 surfactant and tetraethoxyortosilicate in acidic condition and then functionalized by 3-chloropropyltrimethoxysilane. Next, by immobilization of chiral amino acid (S)-2-amino-3-methyl butanoic acid (l-valine) and chiral amino alcohol (S)-2-amino-3-methylbutane-1-ol (l-valinol), preparedviathe reduction ofl-valine by NaBH4/I2in THF, on functionalized-SBA-15, chiral heterogeneous ligands AL*-i-Pr-SBA-15 and AA*-i-Pr-SBA-15 were prepared and characterized by FT-IR, XRD, TGA, EDX, SEM, BET-BJH techniques. The asymmetric allylic oxidation of alkenes was done using copper-complexes of these ligands and the as-synthesized peresters. The reactions were optimized by varying various parameters such as temperature, solvent, amount of chiral heterogeneous ligand, as well as the type and amount of copper salt. Under optimized conditions, 6 mg of AL*-i-Pr-SBA-15 and 3.2 mol% of Cu(CH3CN)4PF6in acetonitrile at 50 °C, the chiral allylic ester was obtained with 80% yield and 39% enantiomeric excess in 24 h. The recyclability of the chiral heterogeneous catalysts was also evaluated without significant reduction in the reaction results up to three runs.
- Samadi, Saadi,Ashouri, Akram,Rashid, Hersh I,Majidian, Shiva,Mahramasrar, Mahsa
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supporting information
p. 17630 - 17641
(2021/10/04)
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- Enantioselective Cascade Biocatalysis for Deracemization of Racemic β-Amino Alcohols to Enantiopure (S)-β-Amino Alcohols by Employing Cyclohexylamine Oxidase and ω-Transaminase
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Optically active β-amino alcohols are very useful chiral intermediates frequently used in the preparation of pharmaceutically active substances. Here, a novel cyclohexylamine oxidase (ArCHAO) was identified from the genome sequence of Arthrobacter sp. TYUT010-15 with the R-stereoselective deamination activity of β-amino alcohol. ArCHAO was cloned and successfully expressed in E. coli BL21, purified and characterized. Substrate-specific analysis revealed that ArCHAO has high activity (4.15 to 6.34 U mg?1 protein) and excellent enantioselectivity toward the tested β-amino alcohols. By using purified ArCHAO, a wide range of racemic β-amino alcohols were resolved, (S)-β-amino alcohols were obtained in >99 % ee. Deracemization of racemic β-amino alcohols was conducted by ArCHAO-catalyzed enantioselective deamination and transaminase-catalyzed enantioselective amination to afford (S)-β-amino alcohols in excellent conversion (78–94 %) and enantiomeric excess (>99 %). Preparative-scale deracemization was carried out with 50 mM (6.859 g L?1) racemic 2-amino-2-phenylethanol, (S)-2-amino-2-phenylethanol was obtained in 75 % isolated yield and >99 % ee.
- Zhang, Jian-Dong,Chang, Ya-Wen,Dong, Rui,Yang, Xiao-Xiao,Gao, Li-Li,Li, Jing,Huang, Shuang-Ping,Guo, Xing-Mei,Zhang, Chao-Feng,Chang, Hong-Hong
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p. 124 - 128
(2020/09/21)
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- Selective hydrogenation of primary amides and cyclic di-peptides under Ru-catalysis
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A ruthenium(II)-catalyzed selective hydrogenation of challenging primary amides and cyclic di-peptides to their corresponding primary alcohols and amino alcohols, respectively, is reported. The hydrogenation reaction operates under mild and eco-benign conditions and can be scaled-up.
- Subaramanian, Murugan,Sivakumar, Ganesan,Babu, Jessin K.,Balaraman, Ekambaram
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supporting information
p. 12411 - 12414
(2020/10/30)
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- Catalytic Mechanism Study on the 1,2- and 1,4-Transfer Hydrogenation of Ketimines and β-Enamino Esters Catalyzed by Axially Chiral Biscarboline-Based Alcohols
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Axial N-O alcohols, which have two large carboline moieties connected to the axis were synthesized and used in catalytic enantioselective 1,2- and 1,4-transfer hydrogenations of total 26 ketimines and β-enamino esters. Excellent levels of enantioselectivity ranging from 91% to 99% were achieved by using catalyst (aS)-(S)-3,3′-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9′-dimethyl-9H,9′H-[1,1′-bipyrido[3,4-b]indole] 2-oxide. Interestingly, a mixture of (aS)-(S)-3,3′-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9′-dimethyl-9H,9′H-[1,1′-bipyrido[3,4-b]indole] 2-oxide and (aR)-(S)-3,3′-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9′-dimethyl-9H,9′H-[1,1′-bipyrido[3,4-b]indole] 2-oxide was also able to provide high enantioselectivities up to 95% that is the same as that using pure (aS)-(S)-3,3′-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9′-dimethyl-9H,9′H-[1,1′-bipyrido[3,4-b]indole] 2-oxide. A plausible catalytic mechanism was suggested and total four kinds of transition states (TS) including almost 60 TS structures were investigated using density functional theory (DFT) with different basis sets such as 6-311G(2d,p). The predicted activation energy data are consistent with the experimental results. (Figure presented.).
- Dong, Mengxian,Wang, Jie,Wu, Shijie,Zhao, Yang,Ma, Yangyang,Xing, Yongfei,Cao, Fei,Li, Longfei,Li, Zhenqiu,Zhu, Huajie
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supporting information
p. 4602 - 4610
(2019/08/30)
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- Synthesis of the Deacetoxytubuvaline Fragment of Pretubulysin and its Lipophilic Analogues for Enhanced Permeability in Cancer Cell Lines
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In the last two decades, tubulysins have emerged as alternatives to microtubule depolymerizing agents such as colchicine and vinblastine, which are well-established anticancer agents. However, the complex structure of tubulysins has always posed a challen
- Reddy, Ramesh B.,Dudhe, Premansh,Chelvam, Venkatesh
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supporting information
p. 77 - 81
(2019/01/04)
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- The Asymmetric Aza-silyl-Prins Reaction: Synthesis of Enantiopure Piperidines
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The design and development of the first asymmetric aza-silyl-Prins reaction is reported, giving rise to valuable and diverse piperidines and pipecolic acid derivatives in both high yields and as single enantiomers. The creation of a novel chiral auxiliary-homoallylic amine for the aza-silyl-Prins reaction is essential to its success.
- Mittapalli, Ramana R.,Guesné, Sebastien J. J.,Parker, Robert J.,Klooster, Wim T.,Coles, Simon J.,Skidmore, John,Dobbs, Adrian P.
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supporting information
p. 350 - 355
(2019/01/11)
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- Asymmetric ring opening of racemic epoxides for enantioselective synthesis of (S)-β-amino alcohols by a cofactor self-sufficient cascade biocatalysis system
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A novel one-pot epoxide hydrolase/alcohol dehydrogenase/transaminase cascade process for the asymmetric ring opening of racemic epoxides to enantiopure β-amino alcohols is reported. The product (S)-β-amino alcohols were obtained in 97-99% ee and 79-99% conversion from readily available racemic epoxides.
- Zhang, Jian-Dong,Yang, Xiao-Xiao,Jia, Qiao,Zhao, Jian-Wei,Gao, Li-Li,Gao, When-Chao,Chang, Hong-Hong,Wei, Wen-Long,Xu, Jian-He
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- Enantioselective Synthesis of Chiral Vicinal Amino Alcohols Using Amine Dehydrogenases
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Chiral vicinal amino alcohols are an important motif found in many biologically active molecules. In this study, biocatalytic reductive amination of α-hydroxy ketones with ammonia was investigated using engineered amine dehydrogenases (AmDHs) derived from the leucine amino acid dehydrogenase (AADH) from Lysinibacillus fusiformis. The AmDHs thus identified enabled the synthesis of (S)-configured vicinal amino alcohols from the corresponding α-hydroxy ketones in up to 99% conversions and >99% ee. One of the AmDH variants was used to prepare a key intermediate for the antituberculosis pharmaceutical ethambutol.
- Chen, Fei-Fei,Cosgrove, Sebastian C.,Birmingham, William R.,Mangas-Sanchez, Juan,Citoler, Joan,Thompson, Matthew P.,Zheng, Gao-Wei,Xu, Jian-He,Turner, Nicholas J.
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p. 11813 - 11818
(2019/12/02)
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- Synthetic studies towards lagunamide C: Polyketide assembly investigations
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Lagunamide C is a depsipeptide natural product with low nM cytotoxicity towards numerous cancer cell lines. Synthetically, it is disconnected to a pentapeptide backbone and polyketide unit that possesses four stereogenic centers, of which two of centers are in question (C38 & 40). Our model system highlights a high-selective aldol addition via a Crimmin's auxiliary setting the C40 ester linkage, and a non-facially selective cyclopropanation with subsequent ring opening for the installation of the C38 methyl center.
- Fatino, Anthony,Weese, Chelsea,Valdez, Salvador,Jiménez-Somarribas, Alberto,Rafferty, Ryan J.
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p. 624 - 627
(2018/01/16)
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- Asymmetric Sulfinylations of N-Methylephedrine-Modified Tri- or Tetraalkyl Zincates by Symmetric Diaryl Sulfoxides
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Diethylzinc was treated with 1 or 2 equiv. of AlkMgCl or PhMgBr (preferably) or with 1 equiv. of nBuLi (less efficiently) for forming species – plausibly zincates – which were sulfinylated by diaryl sulfoxides to give racemic alkyl aryl sulfoxides in yields reaching 100 %. Dialkylzinc reagents were also activated by treatments with 1 or 2 equiv. of an enantiomerically pure alkylmagnesium β-aminoalkoxide. This worked best when the alkoxide stemmed from a dialkylmagnesium reagent and an equimolar amount of N-methyl-(–)-ephedrine. This second activation mode allowed sulfinylations of what was originally the dialkylzinc reagent with diaryl sulfoxides. This generated alkyl aryl sulfoxides with enantiomeric ratios up to 93:7 in up to 100 % yield.
- Ruppenthal, Simon,Brückner, Reinhard
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supporting information
p. 2518 - 2530
(2018/06/11)
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- Total Enantioselective Synthesis of the Endophytic Fungal Polyketide Phomolide H and Its Structural Revision
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A total synthesis of the proposed structure of the natural polyketide-macrolactone phomolide H 2 has been achieved following a bidirectional strategy from l-tartaric acid. The originally assigned structure of phomolide H displayed discordant NMR spectroscopic data in comparison with synthetic 2. The synthetic strategy was extended to prepare diastereomers and epimeric methyl-ethers of the natural product, structural analysis of which revealed a match of the natural product with diastereomer 27. The structural revision of phomolide H from 2 to the methanol solvate of compound 27 is presented.
- McNulty, James,McLeod, David
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supporting information
p. 29 - 33
(2017/01/14)
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- Enantioselective Total Synthesis of the Proposed Structure of the Endophytic Fungal Metabolite Phomolide G: Structural Revision and Unambiguous Stereochemical Assignment
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A total synthesis of the proposed structure of the natural macrolactone phomolide G (1) by a bidirectional strategy from L-tartaric acid is reported. The ω-terminus of the molecule was elaborated by nitrile extension, C3-alkylation and a substrate-controlled 1,3-ketone reduction. The α-terminus was extended by a C2aldehyde-to-alkenal homologation followed by an auxiliary controlled aldol reaction. Macrolactonization and deprotection yielded compound 1 (confirmed by X-ray analysis). This putative structure of phomolide G displayed discordant NMR spectroscopic data in comparison with those of the natural product. Detailed inspection of all NMR spectroscopic data available indicated phomolide G to be likely a diastereomer of 1. The synthetic strategy developed allows control of the absolute stereochemistry at all four chiral secondary alcohol groups. Further manipulation allowed for the preparation of diastereomer 33, the1H and13C NMR spectroscopic data of which are in full accord with that reported for the natural product.
- McNulty, James,McLeod, David,Jenkins, Hilary A.
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supporting information
p. 688 - 692
(2017/01/18)
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- Copper(II) complexes of pyridine-oxazoline (Pyox) ligands: Coordination chemistry, ligand stability, and catalysis
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The coordination chemistry of copper(II) complexes bearing pyridine-oxazoline ("Pyox") ligands has been studied, with an aim of investigating their catalytic ability. Interestingly, the stability of the coordinated ligands has been shown to be much less than previously assumed: hydrolysis of the ligands by fortuitous water gives rise to 2-pyridine carboxylate formation, which encapsulate the copper in a two-dimensional coordination polymer 3. The complexes [Cu(R-Pyox)(NCMe)2(ClO4)2] {R = benzyl (Bn) 2a, phenyl (Ph) 2b, isopropyl (iPr) 2c} have been prepared, of which the benzyl derivative has been analysed by CW EPR spectroscopy. The complex [Cu(Bn-Pyox)(NCMe)2(ClO4)2] and the afore-mentioned coordination polymer have been crystallographically characterised. The performance of complexes 2a-c in the asymmetric allylic oxidation of cyclohexene is described.
- Hallett, Andrew J.,O'Brien, Thomas M.,Carter, Emma,Kariuki, Benson M.,Murphy, Damien M.,Ward, Benjamin D.
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- Enantiospecific C-H Activation Using Ruthenium Nanocatalysts
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The activation of C-H bonds has revolutionized modern synthetic chemistry. However, no general strategy for enantiospecific C-H activation has been developed to date. We herein report an enantiospecific C-H activation reaction followed by deuterium incorporation at stereogenic centers. Mechanistic studies suggest that the selectivity for the α-position of the directing heteroatom results from a four-membered dimetallacycle as the key intermediate. This work paves the way to novel molecular chemistry on nanoparticles.
- Taglang, Céline,Martínez-Prieto, Luis Miguel,Del Rosal, Iker,Maron, Laurent,Poteau, Romuald,Philippot, Karine,Chaudret, Bruno,Perato, Serge,Sam Lone, Ana?s,Puente, Céline,Dugave, Christophe,Rousseau, Bernard,Pieters, Grégory
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supporting information
p. 10474 - 10477
(2015/09/02)
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- Combining Low-Pressure CO2 Capture and Hydrogenation to Form Methanol
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This paper describes a novel approach to CO2 hydrogenation, in which CO2 capture with aminoethanols at low pressure is coupled with hydrogenation of the captured product, oxazolidinone, directly to MeOH. In particular, (2-methylamino)ethanol or valinol captures CO2 at 1-3 bar in the presence of catalytic Cs2CO3 to give the corresponding oxazolidinones in up to 65-70 and 90-95% yields, respectively. Efficient hydrogenation of oxazolidinones was achieved using PNN pincer Ru catalysts to give the corresponding aminoethanol (up to 95-100% yield) and MeOH (up to 78-92% yield). We also have shown that both CO2 capture and oxazolidinone hydrogenation can be performed in the same reaction mixture using a simple protocol that avoids intermediate isolation or purification steps. For example, CO2 can be captured by valinol at 1 bar with Cs2CO3 catalyst followed by 4-isopropyl-2-oxazolidinone hydrogenation in the presence of a bipy-based pincer Ru catalyst to produce MeOH in 50% yield after two steps.
- Khusnutdinova, Julia R.,Garg, Jai Anand,Milstein, David
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p. 2416 - 2422
(2015/04/14)
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- Catalytic hydrogenation of amino acids to amino alcohols with complete retention of configuration
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Rh-MoOx/SiO2 is an effective heterogeneous catalyst for selective hydrogenation of amino acids to amino alcohols in a water solvent. MoOx modification of Rh drastically enhanced the activity and improved the selectivity and ee. Various amino alcohols were obtained in high yields (90-94%) with complete retention of configuration. This journal is the Partner Organisations 2014.
- Tamura, Masazumi,Tamura, Riku,Takeda, Yasuyuki,Nakagawa, Yoshinao,Tomishige, Keiichi
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p. 6656 - 6659
(2014/06/10)
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- Readily available ferrocenyl-phosphinite ligands for Ru(II)-catalyzed enantioselective transfer hydrogenation of ketones and fabrication of hybrid heterojunctions
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A variety of phosphinite based on ferrocenyl moiety possessing central chirality have been screened as ligands for ruthenium(II)-catalyzed transfer hydrogenation of acetophenone derivatives using iso-PrOH as the hydrogen source to afford the corresponding product, (R) or (S)-1-phenylethanol derivatives with high conversions and good enantioselectivities. These complexes were also employed in the asymmetric reduction of different prochiral ketones (up to 85% ee). A comparison of the catalytic properties of amino alcohols and other analogs based on ferrocenyl backbone is also discussed briefly. The structures of these ligands and their corresponding complexes have been elucidated by a combination of multinuclear NMR spectroscopy, IR spectroscopy and elemental analysis. Furthermore, organic-inorganic hybrid heterojunctions were also fabricated by forming thin films of ruthenium(II) complexes on n-Si and evaporation of Au as front contact. Current-voltage (I-V) characteristics of the structures showed excellent rectification properties. Electrical parameters including ideality factor, barrier height and series resistance were determined using I-V and capacitance-voltage (C-V) data. Finally, photoelectrical properties of the structures were examined by means of a solar simulator with AM1.5 global filter.
- Ak, Bünyamin,Aydemir, Murat,Ocak, Yusuf Selim,Durap, Feyyaz,Kayan, Cezmi,Baysal, Akin,Temel, Hamdi
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p. 244 - 253
(2013/12/04)
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- Catalytic anions embedded into avidin: Importance of their chirality and the chiral environment on the stereocontrol of the aldol reaction
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Several catalytic anions bearing a pseudo-dipeptide scaffold, in combination with a biotinylated imidazolium cation, were prepared. The assembly of these salts with avidin resulted in the formation of stable biohybrid catalysts, active in ionic liquid/aqueous media for the aldol reaction. By using natural and non-natural amino alcohols as "side chains" for the proline derivative anion, we studied the cooperativity between the anion and its position in avidin. Taking advantage of the large freedom of movement of the anion inside avidin, we also investigated the substrate scope of this type of biohybrid catalyst.
- Gauchot, Vincent,Schmitzer, Andreea R.
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p. 2694 - 2701
(2014/04/17)
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- New chiral 4-substituted 2-cyanoethyl-oxazolines: Synthesis and assessment of some biological activities
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This paper describes the synthesis of new enantiomerically pure 2-cyanoethyl-oxazolines in one step starting from a wide range of amino alcohols and 4-ethoxy-4-iminobutanenitrile with high to good yields (73-96%) via an appropriate procedure which can be used for a selective synthesis of mono-oxazolines. A simple operation as well as a practical separation is additional eco-friendly attributes of this method. All the synthesized compounds were identified and characterized with their physicochemical features and their spectral data (1H NMR, 13C NMR and TOFMS ES+). Among the prepared mono-oxazolines, the mono-oxazoline (3a) [3-[(4S)-4-benzyl-4,5-dihydro-1,3-oxazol-2-yl] propanenitrile] was tested to detect some biological activities. This compound was studied in vitro given the various types of pharmacological properties characterizing these compounds such as antioxidant, antimicrobial and analgesic activities. The antioxidant activity and mechanism of (3a) were identified using various in vitro antioxidant assays including 1,1-diphenyl-2-picryl-hydrazyl (DPPH), and superoxide anion radicals (O2-) scavenging activity. In addition, compared to Quercetin, the tested synthetic product reveals a relatively-strong antiradical activity towards the DPPH (activity percentage of 81.22%) free radicals and significantly decreased the reactive oxygen species such as (O2 -) formation evaluated by the non-enzymatic (nitroblue tetrazolium/riboflavine) and the enzymatic (xanthine/xanthine oxidase) systems. Related activity values were, respectively, 66% and 60.30%. The oxazoline (3a) showed a high ability to reduce the O2- generation and proved to be a very potent radical scavenger. On the other hand, the analgesic property of the 3[(4S)-benzyl-4,5-dihydro-1,3-oxazol-2-yl] propanenitrile (3a) was demonstrated. The subcutaneous administration of (3a) produced a significant reduction in the number of abdominal constrictions amounting to 73.81% in the acetic acid writhing test in mice. In addition to these advances, the oxazoline (3a) has been investigated as an antimicrobial agent. Our results showed that this molecule exhibited various levels of antibacterial effect against all the tested bacterial strains.
- Hassani, Rym,Kacem, Yakdhane,Ben Mansour, Hedi,Ben Ammar, Hamed,Ben Hassine, Béchir
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- Synthesis of salicylic acid-based 1,3,4-oxadiazole derivatives coupled with chiral oxazolidinones: Novel hybrid heterocycles as antitumor agents
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A series of novel salicylic acid-based 1,3,4-oxadiazoles derivatives coupled with chiral oxazolidinones were synthesized to screen for their in vitro antitumor activity against five human cancer cell lines. Some of these compounds showed good antitumor activities with IC50values ranging from 31.19-57.21 μM. Among the tested compounds 11, 15, 19,23,24, and 34 showed broad-spectrum antitumor activity against all the cell lines. In particular, compound 19 revealed remarkable antitumor activity with IC50 = 31.19-41.87 μM. A431 was the most sensitive cell line against all the compounds studied, followed by HeLa, MCF-7, A549 and HepG2. Structures of newly synthesized compounds were confirmed by IR,1 H NMR, 13C NMR and HRMS spectral data
- Murty,Penthala, Raju,Nath, Lekshmi R.,Anto, Ruby John
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p. 1133 - 1142
(2015/03/31)
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- Synthesis of iron P-N-P' and P-NH-P asymmetric hydrogenation catalysts
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Complexes of the type mer,trans-[Fe(P-N-P)(CO)2Br]BF4 are known to be precatalysts for the asymmetric direct hydrogenation of ketones and imines. Employing related ligand scaffolds, we successfully generated and tested the series of three new precatalysts [Fe(PCy2CH2CH-NCH(R)CH2PPh2)(CO)2Br]BF4 with chirality derived from (S)-amino alcohols with phenyl, benzyl, and isopropyl substituents (R), yielding fairly active and selective systems. For the reduction of acetophenone to (S)-1-phenylethanol turnover frequencies up to 920 h-1 and up to 74% enantiomeric excess at 50 °C and 5-25 atm of H2 were obtained. We found, however, that placing these large groups R next to nitrogen was found to be deleterious to catalytic activity. Extending the scope of the ligand structure, we then developed a series of six P-N-P and five P-NH-P systems starting with o-diphenylphosphinobenzaldehyde and the phosphine-amines PPh2CHR1CHR2NH2 (R1 = H, Ph, CH2Ph, iPr with R2 = H or R1 = Me, Ph with R2 = Ph) as well as their corresponding [Fe(P-N-P)(NCMe)3][BF4]2 and [Fe(P-NH-P)(NCMe)3][BF4]2 complexes, which were not catalytically active. Finally, we made the new achiral iron complex mer,cis-Fe(PPh2(o-C6H4)CHNCH2CH2PPh2)(CO)Br2, which was active for the direct hydrogenation of acetophenone, achieving turnover frequencies of 800 h-1 at 50°C and 25 atm of H2.
- Sonnenberg, Jessica F.,Lough, Alan J.,Morris, Robert H.
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supporting information
p. 6452 - 6465
(2015/02/19)
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- Distinctive meta-directing group effect for iridium-catalyzed 1,1-diarylalkene enantioselective hydrogenation
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An iridium-catalyzed asymmetric hydrogenation of 1,1-diarylkenes is described. Employing a novel, modular phosphoramidite ligand, PhosPrOx, in this transformation affords biologically relevant 1,1-diarylmethine products in good enantiomeric ratios (96.5:3
- Bess, Elizabeth N.,Sigman, Matthew S.
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supporting information
p. 646 - 649
(2013/04/10)
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- Ionic liquid crystals derived from amino acids
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Novel chiral amino acid derived ionic liquid crystals with amine and amide moieties as spacers between the imidazolium head group and the alkyl chain were synthesised. The key step in the synthesis utilised the relatively uncommon SO3 leaving group in a microwave-assisted reaction. The mesomorphic properties of the mesogens were determined by differential scanning calorimetry (DSC), polarising optical microscopy (POM) and X-ray diffraction. All liquid crystalline salts exhibit a smecticA mesophase geometry with strongly interdigitated bilayer structures. An increase of the steric bulk of the stereogenic centre hindered the formation of mesophases. In case of phenylalanine-derived derivatives a mesomorphic behaviour was observed for shorter alkyl chains as compared to other amino acid derivatives indicating an additional stabilising effect by the phenyl moiety. Ionic liquid crystals from amino acids: Novel chiral amino acid derived imidazolium salts with amine or amide units were prepared through the sulfamidate. Depending on the steric bulk of the R group, the chain lengths and the type of anion X, stable SmA phases were detected (see scheme; Bn=benzyl). Copyright
- Mansueto, Markus,Frey, Wolfgang,Laschat, Sabine
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supporting information
p. 16058 - 16065
(2014/04/03)
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- Enantio- and diastereoselective palladium catalysed arylative and vinylative allene carbocyclisation cascades
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The enantioselective synthesis of heavily decorated spirolactams has been accomplished via an arylative or vinylative allene carbocyclisation cascade. Mediated by silver phosphate, a range of allene-linked pro-nucleophiles and aryl or vinyl iodides were reacted in the presence of catalytic Pd(OAc)2 and chiral bis(oxazoline) ligands to afford the spirolactam products in good yields and high enantio- and diastereoselectivities. The Royal Society of Chemistry 2013.
- Li, Meiling,Hawkins, Alison,Barber, David M.,Bultinck, Patrick,Herrebout, Wouter,Dixon, Darren J.
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supporting information
p. 5265 - 5267
(2013/06/27)
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- Tetrahydroquinoline-derived macrocyclic toolbox: The discovery of antiangiogenesis agents in zebrafish assay
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A novel approach to incorporate the macrocyclic rings onto the privileged substructure, i.e., tetrahydroquinoline scaffold, is developed. The presence of an amino acid-derived moiety in the macrocyclic skeleton provides an opportunity to modulate the nature of the chiral side chain. Further, evaluation in a zebrafish screen identified three active small molecules (2.5b, 3.2d, and 4.2) as antiangiogenesis agents at 2.5 μM.
- Reddy Guduru, Shiva Krishna,Chamakuri, Srinivas,Chandrasekar, Gayathri,Kitambi, Satish Srinivas,Arya, Prabhat
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supporting information
p. 666 - 670
(2013/07/26)
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- Tunable ferrocenyl-phosphinite ligands for the ruthenium(II)-catalyzed asymmetric transfer hydrogenation of ketones
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We report here new examples of enantiomerically pure monodendate phosphinite ligands containing both a ferrocene moiety and NH bridging moiety adjacent to the stereocenter, as well as their ruthenium(II) dichloro complexes. The phosphinites based on ferrocenyl moiety possessing stereogenic center have been screened as ligands for ruthenium(II)-catalyzed transfer hydrogenation of aromatic ketones to give corresponding secondary alcohols using iso-PrOH as the hydrogen source in the presence of NaOH. Up to 99% conversion with 97% ee was obtained in the transfer hydrogenation of acetophenone derivatives. Furthermore, the catalytic properties of these catalysts based on ferrocenyl-phosphinite backbone are also discussed briefly. The structures of these ligand and their corresponding complexes have been elucidated by a combination of multinuclear NMR spectroscopy, IR spectroscopy and elemental analysis.
- I?ik, U?ur,Aydemir, Murat,Meri?, Nermin,Durap, Feyyaz,Kayan, Cezmi,Temel, Hamdi,Baysal, Akin
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p. 225 - 233
(2013/10/08)
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- Building a macrocyclic toolbox from C-linked carbohydrates identifies antiangiogenesis agents from zebrafish assay
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We report the synthesis of four different types of macrocyclic-derived glycohybrids from carbohydrates that have an amino acid moiety in the large-ring skeleton. These macrocyclic glycohybrids were obtained from α-C-1H- and β-C-1H-linked carbohydrates. In one series, we utilized ring-closing metathesis as the "stitching technology" to obtain two different macrocycles, i.e., trans equatorial-axial C-1H and C-5H and cis axial-axial C-1H and C-5H. The click approach was the key reaction in our second series to obtain two other macrocyclic compounds, i.e., trans equatorial-axial C-1H and C-5H and cis axial-axial C-1H and C-5H. The evaluation of this toolbox resulted in the identification of two unique compounds as antiangiogenesis agents in an embryonic zebrafish assay. Interestingly, in both cases, the macrocyclic compounds that have a cis relationship (i.e., axial-axial orientation) between C-1H and C-5H showed activity and their other diastereomers (i.e., equatorial-axial C-1H and C-5 H) with a trans relationship did not show any effect. The synthesis of four different types of macrocyclic glycohybrids that contain an amino acid moiety in the large-ring skeleton is reported. Ring-closing metathesis and click chemistry approaches were utilized to obtain two different series of macrocycles. The evaluation of this toolbox resulted in the identification of two unique compounds as antiangiogenesis agents in an embryonic zebrafish assay. Copyright
- Jogula, Srinivas,Dasari, Bhanudas,Khatravath, Mahender,Chandrasekar, Gayathri,Kitambi, Satish Srinivas,Arya, Prabhat
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supporting information
p. 5036 - 5040
(2013/11/06)
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- Coordinating chiral ionic liquids
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A practical synthesis of novel coordinating chiral ionic liquids with an amino alcohol structural motif was developed starting from commercially available amino alcohols. These basic chiral ionic liquids could be successfully applied as catalysts in the asymmetric alkylation of aldehydes and gave high enantioselectivities of up to 91% ee.
- Vasiloiu, Maria,Leder, Sonja,Gaertner, Peter,Mereiter, Kurt,Bica, Katharina
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p. 8092 - 8102
(2013/12/04)
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- Two modes of asymmetric polymerization of phenylacetylenes having an L -amino alcohol residue and two hydroxy groups
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Four novel chiral phenylacetylenes having an L-amino alcohol residue and two hydroxymethyl groups were synthesized and polymerized by an achiral catalyst ((nbd)Rh+[η6-(C6H5)B -(C6H5)3]) or a chiral catalytic system ([Rh(nbd)Cl]2/(S)- or (R)-phenylethylamine ((S)- or (R)-PEA)). The two resulting polymers having an L-valinol or L-phenylalaninol residue showed Cotton effects at wavelengths around 430 nm. This observation indicated that they had an excess of one-handed helical backbones. Positive and negative Cotton effects were observed only for the polymers having an L-valinol residue produced by using (R)- and (S)-PEA as a cocatalyst, respectively, although the monomer had the same chirality. Even when the achiral catalyst was used, the two resulting polymers having an L-valinol or L-phenylalaninol residue showed Cotton effects despite the long distance between the chiral groups and the main chain. We have found the first example of a new type of chiral monomer, that is, a chiral phenylacetylene monomer having an L-amino alcohol residue and two hydroxy groups that was suitable for both modes of asymmetric polymerization, that is, the helix-sense-selective polymerization (HSSP) with the chiral catalytic system and the asymmetric-induced polymerization (AIP) with the achiral catalyst. The other two monomers having L-alaninol and L-tyrosinol were found to be unsuitable to neither HSSP nor AIP because of their polymers' low solubility.
- Jia, Hongge,Li, Jun,Zang, Yu,Aoki, Toshiki,Teraguchi, Masahiro,Kaneko, Takashi
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p. 5134 - 5143
(2013/01/15)
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- Catalytic asymmetric [4+2] annulation initiated by an aza-rauhut-currier reaction: Facile entry to highly functionalized tetrahydropyridines
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Under control: The first example of chiral amino phosphine catalysts for the title reaction between vinyl ketones and N-sulfonyl-1-aza-1,3-dienes has been developed. Under ambient conditions, this protocol provides straightforward access to densely functionalized, enantioenriched tetrahydropyridines with high levels of sterecontrol in good to excellent yields. Copyright
- Shi, Zugui,Yu, Peiyuan,Loh, Teck-Peng,Zhong, Guofu
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supporting information; scheme or table
p. 7825 - 7829
(2012/09/08)
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- Synthesis of imidacloprid derivatives with a chiral alkylated imidazolidine ring and evaluation of their insecticidal activity and affinity to the nicotinic acetylcholine receptor
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A series of imidacloprid (IMI) derivatives with an alkylated imidazolidine ring were asymmetrically synthesized to evaluate their insecticidal activity against adult female housefly, Musca domestica, and affinity to the nicotinic acetylcholine receptor of the flies. The bulkier the alkyl group, the lower was the receptor affinity, but the derivatives methylated and ethylated at the R-5-position of the imidazolidine ring were equipotent to the unsubstituted compound. Quantitative structure-activity relationship (QSAR) analysis of the receptor affinity demonstrated that the introduction of a substituent into the imidazolidine ring was fundamentally disadvantageous, but the introduction of a substituent at the R-5-position was permissible in the case of its small size. The binding model of the synthesized derivatives with the receptor supported the QSAR analysis, indicating the existence of space for a short alkyl group around the R-5-position in the ligand-binding site. In addition, positive correlation was observed between the insecticidal activity and receptor affinity, suggesting that the receptor affinity was the primary factor in influencing the insecticidal activity even if the imidazolidine ring was modified.
- Nishiwaki, Hisashi,Kuriyama, Mituhiro,Nagaoka, Hikaru,Kato, Akira,Yamauchi, Satoshi,Shuto, Yoshihiro,Akamatsu, Miki
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p. 6305 - 6312,8
(2012/12/11)
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- Synthesis of selenium-linked neoglycoconjugates and pseudodisaccharides
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The introduction of organoselenium moieties within the structure of carbohydrates has received attention recently. Herein, we report on the synthesis of selenium-containing neoglycoconjugates and pseudodisaccharides by the reaction of nucleophilic selenium species, generated from sugar diselenides, with chiral N-Boc aziridines and sugar tosylates. The reaction proceeds with moderate to good yields for various substrates. The introduction of organoselenium moieties within the framework of various sugars, with increased levels of complexity, thus allowing the synthesis of disaccharide and glycoconjugate mimetics.
- Affeldt, Ricardo F.,Baldassari, Lucas L.,Luedtke, Diogo S.,Braga, Hugo C.
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p. 10470 - 10475,6
(2012/12/12)
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- Catalytic enantioselective Steglich rearrangements using chiral N-heterocyclic carbenes
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The evaluation of a range of enantiomerically pure NHCs, prepared in situ from imidazolinium or triazolium salt precatalysts, to promote the catalytic enantioselective Steglich rearrangement of oxazolyl carbonates to their C-carboxyazlactones, is reported. Modest levels of enantioselectivity (up to 66% ee) are observed using oxazolidinone derived NHCs.
- Campbell, Craig D.,Concellon, Carmen,Smith, Andrew D.
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experimental part
p. 797 - 811
(2011/08/06)
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- Asymmetric synthesis of β-adrenergic blockers through multistep one-pot transformations involving in situ chiral organocatalyst formation
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Two birds one stone: A new atom-economical one-pot approach to enantioselective chiral drug synthesis, involving in situ multistep organocatalyst formation and the application of the reaction for multistep sequential synthesis of β-adrenergic blockers is disclosed (see scheme).
- Wei, Shengwei,Messerer, Regina,Tsogoeva, Svetlana B.
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supporting information; experimental part
p. 14380 - 14384
(2012/02/01)
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- Azodioxy-carbonyl compounds by oxidation of cyclic imines with m-CPBA
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This article reports a simple and efficient synthesis of C-nitroso compounds (azodioxy esters or ketones and oximes) through a double oxidation of cyclic imines (4,5-dihydrooxazoles and 3,4-dihydro-2H-pyrroles) with m-CPBA. C-Nitroso derivatives seem to b
- Perrone, Serena,Pilati, Tullio,Rosato, Francesca,Salomone, Antonio,Videtta, Valeria,Troisi, Luigino
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scheme or table
p. 2090 - 2095
(2011/04/22)
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- AN IMPROVED PROCESS FOR THE PREPARATION OF ELVITEGRAVIR
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The present invention relates to improved process for the preparation of elvitegravir (12), wherein the compound of formula (6) is protected with suitable protecting agents and further reacted with formula (9) in the presence of tetrakis(triphenylphosphin
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Page/Page column 41
(2011/02/24)
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- One-pot and microwave-assisted synthesis of N-sulfonylaziridines
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A novel and efficient microwave-assisted one-step reaction was developed to synthesize chiral N-sulfonylaziridines by the reaction of different chiral amino alcohols and sulfonic chlorides. The newly developed microwave synthetic method has the advantage of reducing the reaction time from 24 to 0.5 h with improved yields (84-93%) and minimizing by-products.
- Xu, Hao,Tian, Hua,Zheng, Liangyu,Liu, Qingwen,Wang, Li,Zhang, Suoqin
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body text
p. 2873 - 2875
(2011/06/21)
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- Cyclic sulfur ylides derived from gleason-type chiral auxiliaries for the asymmetric synthesis of epoxy amides
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Gleason-type chiral auxiliaries were used for the synthesis of a novel class of sulfonium salts, obtained via methylation of the sulfide with Meerwein's salt. The salts were reacted with aldehydes under basic conditions to provide epoxy amides, which were reduced to their corresponding epoxy alcohols in excellent enantiomeric excesses. Interestingly, it was feasible to synthesize both enantiomeric epoxy alcohols depending on which of the sulfonium salts, prepared from L-amino acids (6 and 9 from L-valine or 15 and 16 from L-serine) was employed.
- Sarabia, Francisco,Vivar-Garcia, Carlos,Garcia-Castro, Miguel,Martin-Ortiz, Jorge
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experimental part
p. 3139 - 3150
(2011/06/22)
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- Salicylaldimine based copper (II) complex: A potential catalyst for the asymmetric Henry reaction
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The chiral ligand synthesized from L-diphenylvalinol and salicylaldehyde is found to catalyse the asymmetric Henry reaction with copper(II)acetate monohydrate. Various nitroaldols were formed with 77-95% ee and good yield. The mechanism for the formation of a particular enantiomer is also discussed. The enantioselection in the formation of the chiral nitroaldol is discussed in terms of steric bulkiness of the catalytic system.
- Ananthi, Nallamuthu,Balakrishnan, Umesh,Velmathi, Sivan
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p. 370 - 379,10
(2020/09/16)
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- Three mechanisms of asymmetric polymerization of phenylacetylenes having an l-amino ether residue and two hydroxy groups
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Three novel chiral phenylacetylenes having an octyloxyethanolamine residue derived from a l-aminoalcohol and two hydroxymethyl groups were synthesized and polymerized by two achiral catalysts ((nbd) Rh+[I?6-(C6H5)B -(C6H5)3] and [Rh(nbd)Cl] 2/triethylamine (TEA)) and a chiral catalytic system ([Rh(nbd)Cl]2/(S)- or (R)-phenylethylamine ((S)- or (R)-PEA)). All of the resulting polymers showed Cotton effects at wavelengths around 430 nm. This observation indicated that they had an excess of one-handed helical backbones. Positive and negative Cotton effects were observed for the polymers having an l-valinol residue produced by using (S)- and (R)-PEA as a cocatalyst, respectively, although the monomers had the same chirality. The two polymers having an l-alaninol or l-phenylalaninol residues obtained by using (S)- and (R)-PEA as a cocatalyst showed CD absorptions with identical signs. Therefore, we found that the chiral monomer having an l-valinol residue was suitable for both modes of asymmetric polymerization, that is, helix-sense-selective polymerization (HSSP) with the chiral catalytic system and asymmetric-induced polymerization (AIP) with the achiral catalysts. However, the other two monomers having an l-alaninol or l-phenylalaninol residue were not suitable for HSSP because the helix sense could not be controlled by the chirality of PEA. To explain the unexpected behaviors in the asymmetric polymerizations of the two chiral monomers having a chiral bidentate ligand, a novel third mechanism of asymmetric polymerization, that is, self-helix-sense-selective polymerization (SHSSP), is proposed in this Article. This Article discusses the contribution of the three mechanisms (AIP, HSSP, and SHSSP) in asymmetric polymerizations of the three monomers.
- Jia, Hongge,Teraguchi, Masahiro,Aoki, Toshiki,Abe, Yunosuke,Kaneko, Takashi,Hadano, Shingo,Namikoshi, Takeshi,Ohishi, Tomoyuki
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experimental part
p. 8353 - 8362
(2011/11/12)
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- The enantioselective intramolecular Morita-Baylis-Hillman reaction catalyzed by amino acid-derived phosphinothiourea
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A series of chiral bifunctional phosphinothioureas derived from l-amino acids have been developed to promote the enantioselective intramolecular Morita-Baylis-Hillman reaction. The process afforded the cyclic hydroxyl enones with up to 84% ee and good yields under mild conditions.
- Gong, Jing-Jing,Yuan, Kui,Song, Hong-Liang,Wu, Xin-Yan
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scheme or table
p. 2439 - 2443
(2010/06/12)
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- Addition of allylzinc to a-amino acid-derived imines: Synthesis of diamino alcohols by Hydroboration
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Imines obtained by condensation of Z-pro- tected or Boc-protected α-amino aldehydes with α-amino tert-butyl esters or with O-silyl-protected amino alcohols were reacted with preformed allyl zinc yielding homoal- lylamines with yields around 50% and selectivities ranging from 50:50 to 90:10. Hydroboration of the terminal double bond furnished diamino alcohols with yields up to 97%. The configuration of the substrates was determined by X-ray-crystallographic analysis of a hydroboration product and comparison of physical data. Springer-Verlag 2010.
- Virlouvet, Mickael,Goesmann, Helmut,Feldmann, Claus,Podlech, Joachim
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experimental part
p. 177 - 198
(2010/08/05)
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- Kinetic resolution of racemic α-arylalkanoic acids with achiral alcohols via the asymmetric esterification using carboxylic anhydrides and acyl-transfer catalysts
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A variety of optically active carboxylic esters are produced by the kinetic resolution of racemic α-substituted carboxylic acids using achiral alcohols, aromatic or aliphatic carboxylic anhydrides, and chiral acyl-transfer catalysts. The combination of 4-methoxybenzoic anhydride (PMBA) or pivalic anhydride with the modified benzotetramisole-type catalyst ((S)-β-Np-BTM) is the most effective for promotion of the enantioselective coupling reaction between racemic carboxylic acids and a novel nucleophile, bis(α-naphthyl) methanol, to give the corresponding esters with high ees. This protocol was successfully applied to the production of nonracemic nonsteroidal anti-inflammatory drugs from racemic compounds utilizing the transacylation process to generate the mixed anhydrides from the acid components with the suitable carboxylic anhydrides.
- Shiina, Isamu,Nakata, Kenya,Ono, Keisuke,Onda, Yu-Suke,Itagaki, Makoto
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supporting information; experimental part
p. 11629 - 11641
(2010/10/04)
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- Cyclosulfamide as a chiral auxiliary: Application to efficient asymmetric synthesis (alkylation/aldolization)
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The chiral cyclosulfamide (S)-2-benzyl-4-isopropyl-1,2,5-thiadiazolidine 1,1-dioxide was designed as a chimera of Evans and Oppolzer chiral auxiliaries. The N-propionyl derivative appeared to be very powerful for the stereocontrolled synthesis of chiral building blocks through asymmetric aldolization and alkylation reactions.
- Fecourt, Fabien,Lopez, Gerald,Lee, Arie Van Der,Martinez, Jean,Dewynter, Georges
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scheme or table
p. 2361 - 2366
(2010/12/20)
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- Simply air: Vanadium-catalyzed oxidative kinetic resolution of methyl o-chloromandelate by ambient air
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Vanadium-catalyzed oxidative kinetic resolution (OKR) of methyl o-chloromandelate 2a, key intermediate of the well-known oral antiplatelet agent (S)-clopidogrel, was achieved by ambient air for the first time. The air oxidation system, which was composed of vanadium and tridentate Schiff base ligands derived from amino alcohols and salicylaldehyde derivatives, afforded an efficient and economic approach to the target intermediate with high enantioselectivities (>99% ee).
- Yin, Lu,Jia, Xian,Li, Xing Shu,Chan, Albert S.C.
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body text
p. 774 - 777
(2011/11/12)
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- PROCESS FOR PREPARING ENANTIOMERICALLY ENRICHED AMINO-ALCOHOLS
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A process for preparing an enantiomerically enriched amino alcohol or derivatives thereof having the structure: wherein C* is a chiral carbon atom and R1 and R2 are independently selected from hydrogen, alkyl, alkoxy, aryl and a peptide chain, wherein said process includes the steps of: (a) providing an amino acid having the structure of Formula I: (b) protecting the amino group of the Formula I amino acid with a carbobenzoxy(Cbz) N-protecting group by reacting the amino acid with benzyl chloroformate in the presence of a base; (c) forming a carboxylic acid alkyl ester of the Cbz N-protected Formula I amino acid by reacting the amino acid with a C1-12 alcohol; and (d) reducing the Cbz N-protected amino acid ester with a borohydride reducing agent in an organic solvent or mixture of organic solvents to form a Cbz N-protected amino-alcohol
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Page/Page column 3
(2010/07/08)
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- Efficient synthesis of functionalized aziridinium salts
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(Chemical Equation Presented) Various aziridinium salts were efficiently prepared from bromination of a series of backbone substituted N,N-bisubstituted β-amino alcohols and isolated via flash column chromatography. The effect of C-substitution, N-substitution, solvent, leaving group, and counter-anions on formation of the isolable aziridinium salts was investigated. 2009 American Chemical Society.
- Chong, Hyun-Soon,Song, Hyun A.,Dadwal, Mamta,Sun, Xiang,Sin, Inseok,Chen, Yunwei
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supporting information; experimental part
p. 219 - 221
(2010/04/24)
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