- Enantio- and Diastereoselective Synthesis of β-Aryl-β-pyrazolyl α-Amino Acid Esters via Copper-Catalyzed Reaction of Azomethine Ylides with Benzylidenepyrazolones
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A fully stereoselective synthesis of unnatural chiral β-aryl-β-pyrazolyl α-amino acid esters via copper-catalyzed addition reactions of azomethine ylides with benzylidenepyrazolones bearing two contiguous stereogenic centers was developed. A 1H-pyrazol-5-ol was introduced by the aromatization of 3H-pyrazol-3-one in the reaction. The transformation operated at room temperature and afforded β-1H-pyrazol-5-ol-α-amino esters in high yields with good to excellent levels of diastereo- and enantioselectivity.
- Gong, Yan-Chuan,Wang, Yue,Li, Er-Qing,Cui, Hao,Duan, Zheng
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supporting information
(2019/02/07)
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- Enantio- And diastereoselective synthesis of b-Aryl-b-pyrazolyl a-amino acid esters via copper-catalyzed reaction of azomethine ylides with benzylidenepyrazolones
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A fully stereoselective synthesis of unnatural chiral b-aryl-b-pyrazolyl a-amino acid esters via copper-catalyzed addition reactions of azomethine ylides with benzylidenepyrazolones bearing two contiguous stereogenic centers was developed. A 1H-pyrazol-5-ol was introduced by the aromatization of 3H-pyrazol-3-one in the reaction. The transformation operated at room temperature and afforded b-1H-pyrazol-5-ol-a-amino esters in high yields with good to excellent levels of diastereo- and enantioselectivity.
- Gong, Yan-Chuan,Wang, Yue,Li, Er-Qing,Cui, Hao,Duan, Zheng
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supporting information
p. 1389 - 1393
(2019/10/28)
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- Lewis-Base-Catalyzed [1 + 2 + 2] Annulation Reaction of Morita-Baylis-Hillman Carbonates with Unsaturated Pyrazolones: Construction of All-Stereogenic Carbon Cyclopentane-Fused Dispiropyrazolones
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The first Lewis-base-catalyzed unexpected [1 + 2 + 2] annulation reaction between Morita-Baylis-Hillman carbonates and unsaturated pyrazolones was developed. The multicyclic cyclopentane-fused dispiropyrazolone constructions containing five contiguous ste
- Liang, Jin-Yan,Shen, Shou-Jie,Chai, Xiao-Qian,Lv, Ting
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p. 12744 - 12752
(2018/10/09)
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- Identification of non-substrate-like glycosyltransferase inhibitors from library screening: Pitfalls & hits
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Bacterial glycosyltransferases are potential targets for the development of novel antibiotics and anti-virulence agents. Most existing glycosyltransferase inhibitors are substrate analogues with limited potential for drug development. The identification of alternative inhibitor chemotypes is therefore of great interest for medicinal chemistry, drug discovery and chemical glycobiology. We describe the application of a biochemical glycosyltransferase assay to screen a small compound library containing three distinct chemical scaffolds (nucleosides, steroids and 5-methyl pyrazol-3-ones) against the retaining α-1,4-galactosyltransferase LgtC from Neisseria meningitidis. While no genuine LgtC inhibitory activity was observed in the nucleoside and steroid series, the best hit compounds in the 5-methyl pyrazol-3-one series showed low micromolar activity. We adapted our assay protocol to develop initial structure-activity relationships in this series, and to establish the target selectivity of the most potent inhibitor over two other glycosyltransferases. Our results provide insights into the activity of this class of non-substrate-like glycosyltransferase inhibitors, and highlight important general pitfalls for inhibitor screening against this enzyme family. Key elements of our experimental design, including a validated single-concentration protocol for inhibitor screening, and our process for elimination of false positives, are, in principle, directly transferable to many other sugar-nucleotide-dependent glycosyltransferases.
- Ema, Masaki,Xu, Yong,Gehrke, Sebastian,Wagner, Gerd K.
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supporting information
p. 131 - 137
(2018/02/07)
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- An asymmetric approach toward chiral multicyclic spirooxindoles from isothiocyanato oxindoles and unsaturated pyrazolones by a chiral tertiary amine thiourea catalyst
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The first organocatalytic Michael-cyclization cascade reaction between isothiocyanato oxindoles and unsaturated pyrazolones has been developed. The multicyclic spiro[oxindole/thiobutyrolactam/pyrazolone] core structures containing three contiguous stereog
- Chen, Qiao,Liang, Jinyan,Wang, Shoulei,Wang, Dong,Wang, Rui
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supporting information
p. 1657 - 1659
(2013/03/14)
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