- Preparation method of (s)-3-hydroxytetrahydrofuran
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The invention provides a preparation method of (s)-3-hydroxytetrahydrofuran. According to the preparation method, ethyl 4-chloroacetoacetate is taken as an initial raw material, (s)-4-chloro-3 hydroxyl-1-butanol is prepared, wherein a substrate is dissolved in a first solvent, an alkali is added, under the catalytic effect of a first catalyst and a second catalyst, asymmetric hydrogenation reaction with hydrogen gas is carried out to produce (s)-4-chloro-3 hydroxyl-1-butanol; chiral 3-hydroxytetrahydrofuran is prepared, wherein prepared chiral 4-chloro-3 hydroxyl-1-butanol is dissolved in a second solvent, an acid is added as a catalyst, and reaction is carried out to obtain (s)-3-hydroxytetrahydrofuran; wherein the first catalyst is a complex generated through reaction of [Ir(COD)Cl]2 with phosphine-pyridine ligand, and the second catalyst is Ru-MACHO complex. The reaction route is short; technology is simple; raw materials are cheap and easily available; production cost is low; reaction process environment pollution is low; product optical purity is high; and the preparation method is suitable for industrialized production.
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Paragraph 0032-0036; 0039-0043; 0046-0050; 0053-0057
(2019/11/13)
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- Oxidative esterification of primary alcohols with TEMPO/CaCl2/Oxone under hydrous conditions
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Symmetric esters are important compounds in the chemical industry, which creates demand for simple and efficient synthetic routes. Oxidative esterification is a promising method to achieve these aims. Here, we show that TEMPO/CaCl2/Oxone forms a convenient catalytic system for the synthesis of the aforementioned symmetric esters from primary alcohols in a biphasic dichloromethane-water solvent mixture. The substrate scope of the reaction method is complementary to those previously published and the terminal oxidant appears to play an important role. In addition, the method is shown to oxidize thiols preferentially over alcohol functional groups to give disulfide-bridged compounds.
- Hackbusch, Sven,Franz, Andreas H.
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p. 2873 - 2876
(2016/06/14)
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- Reduction of aromatic and aliphatic keto esters using sodium borohydride/MeOH at room temperature: a thorough investigation
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Reduction of keto esters is a valuable alternative to produce diols. Sodium borohydride/MeOH system at room temperature and short reaction time efficiently reduced α, β, γ, and δ-keto esters having α-keto esters as the most reactive. The ester functionality was reduced effectively due to the presence of oxo group that somehow facilitates the formation of ring intermediate. As expected, the chemoselective experiments showed that ester functionality was not reduced using this system. This study presents a simple, easy, and benign reduction process of various keto esters to its corresponding diols.
- Kim, Juryoung,De Castro, Kathlia A.,Lim, Minkyung,Rhee, Hakjune
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supporting information; experimental part
p. 3995 - 4001
(2010/07/05)
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- Process for the preparation of 3-hydroxytetrahydrofuran
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An industrial advantage process for producing high-purity 3-hydroxytetrahydrofuran easily and simply, which comprises reducing a 4-halo-3-hydroxybutyric acid ester (1) with a boron hydride compound and/or an aluminum hydride compound as a reducing agent in an organic solvent immiscible with water; treating the reaction mixture with an acid and water to thereby effect conversion to the corresponding 4-halo-1,3-butanediol and at the same time giving an aqueous solution containing said compound; carrying out the cyclization reaction of the 4-halo-1,3-butanediol in said aqueous solution; extracting the resulting 3-hydroxytetrahydrofuran from the 3-hydroxytetrahydrofuran-containing aqueous solution using an organic solvent immiscible with water; and isolating the 3-hydroxytetrahydrofuran by concentration and/or distillation of the solution obtained.
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Page column 13
(2008/06/13)
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