- SYNTHESIS AND APPLICATION OF CHIRAL SUBSTITUTED POLYVINYLPYRROLIDINONES
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Chiral polyvinylpyrrolidinone (CSPVP), complexes of CSPVP with a core species, such as a metallic nanocluster catalyst, and enantioselective oxidation reactions utilizing such complexes are disclosed. The CSPVP complexes can be used in asymmetric oxidation of diols, enantioselective oxidation of alkenes, and carbon-carbon bond forming reactions, for example. The CSPVP can also be complexed with biomolecules such as proteins, DNA, and RNA, and used as nanocarriers for siRNA or dsRNA delivery.
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Paragraph 0022; 0028; 0031
(2020/11/24)
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- TUBULYSINS AND PROTEIN-TUBULYSIN CONJUGATES
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Provided herein are compounds, compositions, and methods for the treatment of diseases and disorders associated with cancer, including tubulysins and protein (e.g., antibody) drug conjugates thereof.
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Paragraph 0014; 00270; 00271
(2020/07/14)
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- Synthesis, antimycobacterial activity and influence on mycobacterial InhA and PknB of 12-membered cyclodepsipeptides
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In recent years, several small natural cyclopeptides and cyclodepsipeptides were reported to have antimycobacterial activity. Following this lead, a synthetic pathway was developed for a small series of 12-membered ring compounds with one amide and two ester bonds (cyclotridepsipeptides). Within the series, the ring system proved to be necessary for growth inhibition of Mycobacterium smegmatis and Mycobacterium tuberculosis in the low micromolar range. Open-chain precursors and analogues were inactive. The compounds modulated autophosphorylation of the mycobacterial protein kinase B (PknB). PknB inhibitors were active at μM concentration against mycobacteria while inducers were inactive. PknB regulates the activity of the mycobacterial reductase InhA, the target of isoniazid. The activity of the series against Mycobacterium bovis BCG InhA overexpressing strains was indistinguishable from that of the parental strain suggesting that they do not inhibit InhA. All substances were not cytotoxic (HeLa > 5 μg/ml) and did not show any significant antiproliferative effect (HUVEC > 5 μg/ml; K-562 > 5 μg/ml). Within the scope of this study, the molecular target of this new type of small cyclodepsipeptide was not identified, but the data suggest interaction with PknB or other kinases may partly cause the activity.
- Laqua, Katja,Klemm, Marcel,Richard-Greenblatt, Melissa,Richter, Adrian,Liebe, Linda,Huang, Tingting,Lin, Shuangjun,Guardia, Ana,Pérez-Herran, Esther,Ballell, Lluís,Av-Gay, Yossef,Imming, Peter
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p. 3166 - 3190
(2018/05/05)
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- Chiral-Substituted Poly-N-vinylpyrrolidinones and Bimetallic Nanoclusters in Catalytic Asymmetric Oxidation Reactions
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A new class of poly-N-vinylpyrrolidinones containing an asymmetric center at C5 of the pyrrolidinone ring were synthesized from l-amino acids. The polymers, particularly 17, were used to stabilize nanoclusters such as Pd/Au for the catalytic asymmetric oxidations of 1,3- and 1,2-cycloalkanediols and alkenes, and Cu/Au was used for C-H oxidation of cycloalkanes. It was found that the bulkier the C5 substituent in the pyrrolidinone ring, the greater the optical yields produced. Both oxidative kinetic resolution of (±)-1,3- and 1,2-trans-cycloalkanediols and desymmetrization of meso cis-diols took place with 0.15 mol % Pd/Au (3:1)-17 under oxygen atmosphere in water to give excellent chemical and optical yields of (S)-hydroxy ketones. Various alkenes were oxidized with 0.5 mol % Pd/Au (3:1)-17 under 30 psi of oxygen in water to give the dihydroxylated products in >93% ee. Oxidation of (R)-limonene at 25 °C occurred at the C-1,2-cyclic alkene function yielding (1S,2R,4R)-dihydroxylimonene 49 in 92% yield. Importantly, cycloalkanes were oxidized with 1 mol % Cu/Au (3:1)-17 and 30% H2O2 in acetonitrile to afford chiral ketones in very good to excellent chemical and optical yields. Alkene function was not oxidized under the reaction conditions. Mechanisms were proposed for the oxidation reactions, and observed stereo- and regio-chemistry were summarized.
- Hao, Bo,Gunaratna, Medha J.,Zhang, Man,Weerasekara, Sahani,Seiwald, Sarah N.,Nguyen, Vu T.,Meier, Alex,Hua, Duy H.
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supporting information
p. 16839 - 16848
(2017/01/10)
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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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p. 797 - 811
(2011/08/06)
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- An efficient synthesis of achiral and chiral 1,2,4-triazolium salts: Bench stable precursors for N-heterocyclic carbenes
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The promising utility of triazolyl N-heterocyclic carbene catalysts in umpolung aldehyde chemistry requires a straight-forward reliable synthesis from readily available materials. Herein, we describe the synthesis of a variety of triazolyl N-heterocyclic
- Kerr, Mark S.,Read De Alaniz, Javier,Rovis, Tomislav
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p. 5725 - 5728
(2007/10/03)
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- Design and synthesis of novel conformationally restricted HIV protease inhibitors
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A set of HIV protease inhibitors represented by compound 2 has previously been described. Structural and conformational analysis of this compound suggested that conformational restriction of the P1/P2 portion of the molecule could lead to a novel set of potent protease inhibitors. Thus, probe compounds 3-7 were designed, synthesized, and found to be potent inhibitors of HIV protease.
- Salituro, Francesco G.,Baker, Christopher T.,Court, John J.,Deininger, David D.,Kim, Eunice E.,Li, Biquin,Novak, Perry M.,Rao, Bhisetti G.,Pazhanisamy,Porter, Margaret D.,Schairer, Wayne C.,Tung, Roger D.
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p. 3637 - 3642
(2007/10/03)
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- Facile stereoselective synthesis of γ-substituted γ-amino acids from the corresponding α-amino acids
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A facile stereoselective method for the synthesis of γ-substituted, γ-amino acids from α-amino acids was developed. The key step of the procedure is complete reduction of the keto functionality of α-amino acyl Meldrum's acid by sodium acetoxyborohydride. The resulting amino alkyl Meldrum's acid undergoes thermal decarboxylative ring closure to a 5-substituted pyrrolidinone which yields the corresponding γ-amino acid after basic hydrolysis. The overall yield of the procedure ranges from 40 to 65%.
- Smrcina, Martin,Majer, Pavel,Majerova, Eva,Guerassina, Tatiana A.,Eissenstat, Michael A.
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p. 12867 - 12874
(2007/10/03)
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- 12. Approaches to the Synthesis of Cytochalasans; Part 9: A Versatile Concept Leading To All Structural Types of Cytochalasans
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Starting from D-glutamic acid (5), the bicyclic compounds 4a and 4b were synthesized via 17 (Schemes 1 and 2).The reaction leading to 4g and 4h with LiCuPh2 was not successful.But treatment of the N-protected model lactams 19, 21, and 22 with Li2Cu(CN)Ph2 gave the amino ketones 24, 26, and 26, respectively (Scheme 3).The desired compound 23 was obtained from 20.Conversion of the unprotected lactams 28, 31, and 32 gave the phenyl derivative 34 in excellent yields.Ester 35 was transformed to the α-amino-γ-oxo-acid derivative 36.This conversion opens a novel access to this type of compounds.
- Ackermann, Jean,Matthes, Michael,Tamm, Christoph
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p. 122 - 132
(2007/10/02)
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