- α,ε-Hybrid foldamers with 1,2,3-Triazole rings: Order versus disorder
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Two epimeric series of foldamers characterized by the presence of a repeating α,ε-dipeptide unit have been prepared and characterized by 1H NMR and ECD spectroscopies together with X-ray diffraction. The first series contains l-Ala and d-4-carboxy-5-methyl-oxazolidin-2-one (d-Oxd). The other series contains l-Ala and l-Oxd. The l,d series of oligomers forms ordered β-turn foldamers, characterized by a 311 pattern. The l,l series is not ordered. Simulations show that an ordered l,l trimer lies more than 2 kcal/mol higher than the more stable nonfolded extended conformations. Cu2+ forms complexes with both series but is not able to order the l,l series. Analysis of the EPR spectra shows that the l,d foldamers bear two types of complexation sites that are assigned as a nitrogen donor of the triazole ring and a carboxylate ligand. The l-Ala-d-Oxd-Tri-CO motif may be introduced in any peptide sequence requiring the presence of a stable β-turn conformations, like in the study of protein-protein interactions.
- Milli, Lorenzo,Larocca, Michele,Tedesco, Mattia,Castellucci, Nicola,Ghibaudi, Elena,Cornia, Andrea,Calvaresi, Matteo,Zerbetto, Francesco,Tomasini, Claudia
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Read Online
- Synthesis method of multi-configuration 2-oxooxazolidine-4-carboxylic acid compound
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The invention relates to a synthesis method of a multi-configuration 2-oxooxazolidine-4-carboxylic acid compound, wherein the synthesis method comprises the following steps: (1) under the protection of inert gas, carrying out a reaction on a compound represented by a formula I or an isomer thereof with S,S'-dimethyl dithiocarbonate in the presence of water to obtain a compound represented by a formula II or an isomer thereof; (2) carrying out hydrolysis reaction on the compound represented by the formula II or the isomer thereof under an alkaline condition to prepare a compound represented bya formula III or an isomer thereof, wherein the structural formula of the compound represented by the formula I is shown in the specification, the structural formula of the compound represented by theformula II is shown in the specification, the structural formula of the compound represented by the formula III is shown in the specification, in the formula I, the formula II and the formula III, Ris one of H and alkyl with 1-5 carbon atoms. According to the method, water is used as a solvent, so that the method is green, environment-friendly, high in safety, easy in reaction operation and easyin reaction condition control, and the product yield is up to 86% or above.
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Paragraph 0048-0050; 0052-0055; 0098-0104
(2020/11/01)
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- Synthesis and evaluation of in vivo anti-hypothermic effect of all stereoisomers of the thyrotropin-releasing hormone mimetic: Rovatirelin Hydrate
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We discovered the orally active thyrotropin-releasing hormone (TRH) mimetic: (4S,5S)-5-methyl-N-{(2S)-1-[(2R)-2-methylpyrrolidin-1-yl]-1-oxo-3-(1,3-thiazol-4-yl)propan-2-yl}-2-oxo-1,3-oxazolidine-4-carboxamide 1 (rovatirelin). The central nervous system (CNS) effect of rovatirelin after intravenous (iv) administration is 100-fold higher than that of TRH. As 1 has four asymmetric carbons in its molecule, there are 16 stereoisomers. We synthesized and evaluated the anti-hypothermic effect of all stereoisomers of 1, which has the (4S),(5S),(2S),(2R) configuration from the N-terminus to the C-terminus, in order to clarify the structure?activity relationship (SAR) of stereoisomers. The (4R),(5R),(2R),(2S)-isomer 16 did not show any anti-hypothermic effect. Only the (4S),(5S),(2S),(2S)-isomer 10, which has the (2S)-2-methylpyrrolidine moiety at the C-terminus showed the anti-hypothermic effect similar to 1. Stereoisomers, which have the (5R) configuration of the oxazolidinone at the N-terminus and the (2R) configuration at the middle-part, showed a much lower anti-hypothermic effect than that of 1. On the other hand, stereoisomers, which have the (4R) configuration of the oxazolidinone at the N-terminus or the (2S) configuration of the C-terminus, have little influence on the anti-hypothermic effect.
- Kobayashi, Naotake,Sato, Norihito,Sugita, Katsuji,Takahashi, Kouji,Sugawara, Tamio,Tada, Yukio,Yoshikawa, Takayoshi
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- HEPATITIS C VIRUS INHIBITORS
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The present disclosure relates to compounds, compositions and methods for the treatment of Hepatitis C virus (HCV) infection. Also disclosed are pharmaceutical compositions containing such compounds and methods for using these compounds in the treatment of HCV infection.
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Page/Page column 89
(2011/07/07)
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- RAPID SYNTHESIS OF β-HYDROXY-α-AMINO ACIDS, SUCH AS L-THREONINE, β-HYDROXYPHENYLALANINE, AND β-HYDROXYLEUCINE, VIA AN APPLICATION OF THE SHARPLESS ASYMMETRIC EPOXIDATION
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The optically active epoxy alcohols 6abc, prepared by a Sharpless kinetic resolution-epoxidation process, were converted to the optically pure β-hydroxy-α-amino acids 1abc in four steps and high overall yield.
- Jung, Michael E.,Jung, Young H.
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p. 6637 - 6640
(2007/10/02)
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- NEW ENTRY TO SYN-β-HYDROXY-α-AMINO ACIDS
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The intramolecular conjugate addition of allylically situated carbamoyloxy group to properly substituted heteroolefin proceeds with complete 1,2-syn diastereoselectivity, which culminates in a highly stereoselective new synthesis of syn-β-hydroxy-α-amino acids.
- Hirama, Masahiro,Hioki, Hideaki,Ito, Sho
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p. 3125 - 3128
(2007/10/02)
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