- A fatty acid glycoside from a marine-derived fungus isolated from mangrove plant Scyphiphora hydrophyllacea
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To study the antimicrobial components from the endophytic fungus A1 of mangrove plant Scyphiphora hydrophyllacea Gaertn. F., a new fatty acid glucoside was isolated by column chromatography from the broth of A1, and its structure was identified as R-3-hydroxyundecanoic acid methylester-3- O-α-L- rhamnopyranoside (1) by spectroscopic methods including 1D and 2D NMR (HMQC, 1H-1H COSY and HMBC) and chemical methods. Antimicrobial assay showed compound 1 possessed modest inhibitory effect on Saphylococcus aureus and methicillin-resistant S. aureus (MRSA) using the filter paper disc agar diffusion method.
- Zeng, Yan-Bo,Wang, Hui,Zuo, Wen-Jian,Zheng, Bo,Yang, Tao,Dai, Hao-Fu,Mei, Wen-Li
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- Enzymatic Regio- And Enantioselective C-H Oxyfunctionalization of Fatty Acids
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Directed evolution of a P450 hydroxylase (P450BSβ) achieves an engineered enzyme that is able to catalyze C-H oxyfunctionalization of fatty acids (FAs) in a highly regio- and enantioselective fashion (>20:1 Cβ/Cα and > 99% ee in all cases). The biocatalyst displays high reactivity (TON up to 1540), takes inexpensive H2O2 as oxidant, and converts C11-C18 saturated FAs as well as naturally derived unsaturated oleic and linoleic acids to optically pure β-hydroxy FAs. Merging biocatalysis with chemical transformation, we further offer a chemoenzymatic strategy to access valuable FA derivatives bearing 1,3-diol, β-amino, β-lactone, and β-lactam functionalities in either enantiomeric form. Molecular docking studies provide a rationale for the regio- and enantioselectivity of this reaction.
- Chen, Hao,Huang, Mengfei,Yan, Wenliang,Bai, Wen-Ju,Wang, Xiqing
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p. 10625 - 10630
(2021/09/02)
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- An efficient method to chiral β-hydroxy acids: Synthesis of lipid-A side chain
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The synthesis of optically active β-hydroxy acids 5a-c is achieved in four steps from their corresponding terminal olefins 1a-c by employing Sharpless asymmetric dihydroxylation. The regioselective ring opening of chiral cyclic sulfites 3a-c with cyanide ion, constitutes the key reaction, thus producing the hydroxy nitriles 4a-c.
- Nandanan,Phukan, Prodeep,Sudalai
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p. 893 - 896
(2007/10/03)
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- Resolution and Asymmetric Synthesis of 3-Hydroxycarboxylic Acids by using (-)-Menthone as a Chiral Template
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1,3-Dioxan-4-ones 6 and 7 derived from (-)-menthone can be utilized in resolution of 3-hydroxycarboxylic acids and asymmetric synthesis of 2-substituted 3-hydroxycarboxylic acids.
- Harada, Toshiro,Yoshida, Tetsuya,Kagamihara, Yasuhiro,Oku, Akira
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p. 1367 - 1370
(2007/10/02)
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- Asymmetric Reduction of Aliphatic Short- to Long-Chain β-Keto Acids by Use of Fermenting Bakers' Yeast
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Eleven β-keto acids, ranging from 3-oxobutanoic to 3-oxooctanoic acids, were reduced with fermenting bakers' yeast to the corresponding optically active β-hydroxy acids, which were isolated as the methyl esters.In all cases, the (R)-hydroxy acids were obtained in >/=98percent ee, except for 3-oxobutanoic acid, which afforded the (S)-hydroxy acid in 86percent ee.Inhibition of fermentation was observed for 3-oxoundecanoic to 3-oxotetradecanoic acids, leading to no reduction.Lowering of the substrate concentration was found to be appreciably effective in avoiding inhibition.
- Utaka, Masanori,Watabu, Hisashi,Higashi, Hiroshi,Sakai, Takashi,Tsuboi, Sadao,Torii, Sigeru
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p. 3917 - 3921
(2007/10/02)
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- ASYMMETRIC SYNTHESIS VIA ACETAL TEMPLATES. 12. HIGHLY DIASTEREOSELECTIVE COUPLING REACTIONS WITH A KETENE ACETAL. AN EFFICIENT, ASYMMETRIC SYNTHESIS OF R-(+)-α-LIPOIC ACID.
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TiCl4 catalyzes the essentially quantitative coupling of chiral acetals 1 with 1-t-butoxy-1-t-butyldimethylsilyloxyethene 2 to generate β-alkoxycarboxylates in wich the new asymmetric center is formed with excellent diastereoselection. β-Hydrocarboxylic acids of high ee result from removal of the chiral auxiliary.The procedure has been appllied to the synthesis of R-(+)-α-lipoic acid 10.
- Elliott, John D.,Steele, John,Johnson, William S.
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p. 2535 - 2538
(2007/10/02)
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- The Reaction of Trialkylvinylborate with Carbon Dioxide. A New Method for the Preparation of β-Hydroxycarboxylic Acids from Alkenes
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Chloromagnesium trialkylvinylborate, (R3BCH=CH2)MgCl, on reaction with carbon dioxide under pressure, followed by oxidation with alkaline hydrogen peroxide, gives a β-hydroxycarboxylic acid.
- Deng, Min-Zhi,Lu, Ding-An,Xu, Wei-Hua
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p. 1478 - 1479
(2007/10/02)
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