91751-55-2Relevant articles and documents
The Mechanism of Dehydrating Bimodules in trans-Acyltransferase Polyketide Biosynthesis: A Showcase Study on Hepatoprotective Hangtaimycin
Deng, Zixin,Dickschat, Jeroen S.,Dong, Yulu,Lu, Junlei,Luo, Minghe,Qi, Miaomiao,Shen, Kun,Sun, Guo,Sun, Yuhui,Tang, Lingjie,Xiang, Jin,Xu, Houchao,Yin, Zhiyong
supporting information, p. 19139 - 19143 (2021/08/03)
A bioassay-guided fractionation led to the isolation of hangtaimycin (HTM) from Streptomyces spectabilis CCTCC M2017417 and the discovery of its hepatoprotective properties. Structure elucidation by NMR suggested the need for a structural revision. A putative HTM degradation product was also isolated and its structure was confirmed by total synthesis. The biosynthetic gene cluster was identified and resembles a hybrid trans-AT PKS/NRPS biosynthetic machinery whose first PKS enzyme contains an internal dehydrating bimodule, which is usually found split in other trans-AT PKSs. The mechanisms of such dehydrating bimodules have often been proposed, but have never been deeply investigated. Here we present in vivo mutations and in vitro enzymatic experiments that give first and detailed mechanistic insights into catalysis by dehydrating bimodules.
Preparation method of gamma-substituted hexadienoic acid
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Paragraph 0019, (2021/01/20)
The invention relates to a preparation method of gamma-substituted hexadienoic acid. The method is characterized by comprising the following steps: (1) at -10-40 DEG C, adding a solvent, a catalyst and a catalytic assistant into a reaction vessel, stirring, introducing oxygen, adding 1-(2-furyl)-1-alkyl methanol, controlling the molar ratio of the catalyst to the catalytic assistant to the 1-(2-furyl)-1-alkyl methanol at 0.0001-5:0.0001-3:100, reacting at 0-200 DEG C under 0.1-20 MPa for 1-74 h, wherein the solvent is a mixed solution composed of a water phase and an organic phase according toa volume ratio of 1:0.01-3, the water phase is a phosphate acidic solution, the organic phase is a reaction inert solvent, the catalyst is a palladium compound, and the catalytic assistant is an amine or phosphine compound; and (2) cooling the reaction vessel to room temperature, adding an organic solvent, extracting, and carrying out reduced pressure distillation on the organic phase. The methodhas the advantages that the defect of technical economy in an existing synthesis route is overcome, the technological process is simplified, consumption and emission are reduced, energy consumption and cost are reduced, and the method is suitable for industrial production for increasing productivity.
Ether-functionalized ionic liquids for nonaqueous biocatalysis: Effect of different cation cores
Zhao, Hua,Kanpadee, Naphatsawan,Jindarat, Chanida
, p. 104 - 112 (2019/03/28)
Ether-functionalized ionic liquids (ILs) usually have low viscosities, and can be designed to be compatible with enzymes. However, there is a lack of understanding of the effect of different ether-functionalized structures on the enzyme activity. We systematically evaluated new ether-functionalized ILs carrying different cation cores (pairing with Tf2N? anions) in two Novozym 435-catalyzed reactions: (1) the transesterification of ethyl sorbate with 1-propanol at 50 °C; (2) the ring-opening polymerization (ROP) of ε-caprolactone at 70 °C. The lipase showed different activities: in the first reaction, [CH3OCH2CH2-Et3N][Tf2N] and [CH3OCH2CH2-Py][Tf2N] gave the highest reaction rates; in the second reaction, [CH3OCH2CH2-PBu3][Tf2N] produced the highest molecular mass (Mw up to 25,400 Da). The lipase's thermal stability in [CH3OCH2CH2-Et3N][Tf2N] was found much higher than that in t-butanol. The fluorescence spectra of free lipase (excited at 280 nm) in these ILs reveal that the wavelength of the maximum emission peak occurred at 314 nm for both [CH3OCH2CH2PBu3][Tf2N] and [CH3OCH2CH2PEt3][Tf2N], which matched closely with that (313 nm) in aqueous phosphate buffer (pH 7.5, 20 mM), while other ether-functionalized ILs led to various degrees of red shifts. In summary, the lipase activity is not only dependent on the IL structure, but also on the substrate and other reaction conditions.
