- Diastereoselective Synthesis of Methyl α-Kedarosaminide, a Carbohydrate Moiety of the Enediyne Antitumor Antibiotic Kedarcidin Chromophore
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Methyl α-kedarosaminide (9), a carbohydrate moiety of the enediyne antitumor antibiotic kedarcidin chromophore, was synthesised from D-threonine.Stereoselective reduction of the allyl ketone 5 derived from D-threonine was a key step in the synthesis, which was achieved by using Me4NBH(OAc)3 for intramolecular hydride delivery.
- Vuljanic, Tatjana,Kihlberg, Jan,Somfai, Peter
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- Novel chiral stationary phases based on 3,5-dimethyl phenylcarbamoylated β-cyclodextrin combining cinchona alkaloid moiety
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Novel chiral selectors based on 3,5-dimethyl phenylcarbamoylated β-cyclodextrin connecting quinine (QN) or quinidine (QD) moiety were synthesized and immobilized on silica gel. Their chromatographic performances were investigated by comparing to the 3,5-dimethyl phenylcarbamoylated β-cyclodextrin (β-CD) chiral stationary phase (CSP) and 9-O-(tert-butylcarbamoyl)-QN-based CSP (QN-AX). Fmoc-protected amino acids, chiral drug cloprostenol (which has been successfully employed in veterinary medicine), and neutral chiral analytes were evaluated on CSPs, and the results showed that the novel CSPs characterized as both enantioseparation capabilities of CD-based CSP and QN/QD-based CSPs have broader application range than β-CD-based CSP or QN/QD-based CSPs. It was found that QN/QD moieties play a dominant role in the overall enantioseparation process of Fmoc-amino acids accompanied by the synergistic effect of β-CD moiety, which lead to the different enantioseparation of β-CD-QN-based CSP and β-CD-QD-based CSP. Furthermore, new CSPs retain extraordinary enantioseparation of cyclodextrin-based CSP for some neutral analytes on normal phase and even exhibit better enantioseparation than the corresponding β-CD-based CSP for certain samples.
- Zhu, Lunan,Zhu, Junchen,Sun, Xiaotong,Wu, Yaling,Wang, Huiying,Cheng, Lingping,Shen, Jiawei,Ke, Yanxiong
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p. 1080 - 1090
(2020/05/25)
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- Total Synthesis of Teixobactin
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The first total synthesis of the cyclic depsipeptide natural product teixobactin is described. Synthesis was achieved by solid-phase peptide synthesis, incorporating the unusual l-allo-enduracididine as a suitably protected synthetic cassette and employing a key on-resin esterification and solution-phase macrolactamization. The synthetic natural product was shown to possess potent antibacterial activity against a range of Gram-positive pathogenic bacteria, including a virulent strain of Mycobacterium tuberculosis and methicillin-resistant Staphylococcus aureus (MRSA).
- Giltrap, Andrew M.,Dowman, Luke J.,Nagalingam, Gayathri,Ochoa, Jessica L.,Linington, Roger G.,Britton, Warwick J.,Payne, Richard J.
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supporting information
p. 2788 - 2791
(2016/06/15)
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- Total synthesis of chloptosin, a potent apoptosis-lnducing cyclopeptide
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Chemical Equation Presentation A bidirectional total synthesis of chloptosin has been achieved in 16 operations (32 individual reactions) and 3% overall yield from the readily available materials. Palladium-catalyzed tryptophan synthesis, diastereoselective selenocyclization and oxidative deselenation successfully served as key steps In construction of the dimeric core amino acid. 2-Bromo-1-ethyl pyridinium tetrafluoroborate was efficiently employed In the peptide couplings with spatial encumbrance In this synthesis.
- Yu, Shun-Ming,Hong, Wen-Xu,Wu, Yuan,Zhong, Chun-Long,Yao, Zhu-Jun
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supporting information; experimental part
p. 1124 - 1127
(2010/06/13)
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