- Preparation method of remdesivir intermediate 2-ethyl-1-butanol
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The invention relates to a preparation method of a remdesivir intermediate 2-ethyl-1-butanol. The preparation method comprises a step of substitution reaction, namely a step of carrying out a substitution reaction on alkyl acetoacetate and halogenated ethane under an alkaline condition to obtain alkyl 2-ethyl-3-oxo-butyrate; a step of addition reduction, namely a step of carrying out an addition reduction reaction on the alkyl 2-ethyl-3-oxo-butyate to obtain alkyl 2-ethylbutyrate; a step of reduction, namely a step of subjecting the alkyl 2-ethylbutyrate to a reduction reaction to prepare 2-ethyl-1-butanol (I). According to the preparation method of the remdesivir intermediate 2-ethyl-1-butanol, the alkyl acetoacetate and halogenated ethane serve as main raw materials, the raw materials are simple and easy to obtain, the 2-ethyl-1-butanol (I) is prepared through substitution reaction, addition reduction and reduction reaction, the process is simple, economical and environmentally friendly, the product is convenient to obtain, and industrial production of remdesivir bulk drugs is facilitated.
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Paragraph 0045-0046
(2020/08/09)
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- Catalytic Enantioselective Protonation/Nucleophilic Addition of Diazoesters with Chiral Oxazaborolidinium Ion Activated Carboxylic Acids
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A new chiral Br?nsted acid derived from carboxylic acid and a chiral oxazaborolidinium ion (COBI), as an activator, is introduced. This acid was successfully applied as a catalyst for the highly enantioselective protonation/nucleophilic addition of diazoesters with carboxylic acids.
- Kang, Ki-Tae,Kim, Seung Tae,Hwang, Geum-Sook,Ryu, Do Hyun
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supporting information
p. 3977 - 3981
(2017/03/27)
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- Enantioselective Palladium-Catalyzed Carbene Insertion into the N?H Bonds of Aromatic Heterocycles
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C3-substituted indoles and carbazoles react with α-aryl-α-diazoesters under palladium catalysis to form α-(N-indolyl)-α-arylesters and α-(N-carbazolyl)-α-arylesters. The products result from insertion of a palladium-carbene ligand into the N?H bond of the aromatic N-heterocycles. Enantioselection was achieved using a chiral bis(oxazoline) ligand, in many cases with high enantioselectivity (up to 99 % ee). The method was applied to synthesize the core of a bioactive carbazole derivative in a concise manner.
- Arredondo, Vanessa,Hiew, Stanley C.,Gutman, Eugene S.,Premachandra, Ilandari Dewage Udara Anulal,Van Vranken, David L.
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supporting information
p. 4156 - 4159
(2017/04/03)
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- Redox-Annulation of Cyclic Amines and β-Ketoaldehydes
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Benzo[a]quinolizine-2-one derivatives are readily assembled from 1,2,3,4-tetrahydroisoquinoline and β-ketoaldehydes by means of a new intramolecular redox-Mannich process. These reactions are promoted by simple acetic acid and are thought to involve azomethine ylides as reactive intermediates.
- Chen, Weijie,Seidel, Daniel
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supporting information
p. 1024 - 1027
(2016/03/15)
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- Catalytic hydroalkylation of olefins by stabilized carbon nucleophiles promoted by dicationic platinum(II) and palladium(II) complexes
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The coordinated olefin in dicationic platinum(II) and palladium(II) complexes [M(PNP)(olefin)](SbF6)2 (M = Pt, Pd; PNP = 2,6-bis(diphenylphosphinomethyl)pyridine; olefin = ethylene, propylene) reacts with β-dicarbonyl compounds (pentane-2,4-dione and methyl-3-oxobutanoate). If the proton released after the nucleophilic attack is trapped by a base, stable σ-alkyl derivatives [(PNP)M-CH2-CH(R)CH(Ac)COR′] SbF6 (R = H, Me; R′ = Me, OMe) are formed; otherwise the M-C σ-bond can be cleaved by the proton, in the rate-determining step of a catalytic cycle that leads to the alkylated dicarbonyl compound. The β-diketone is intrinsically more reactive than the β-ketoester, but in the catalytic reaction of the former an inhibition effect is observed in the case of the platinum catalyst.
- Cucciolito, Maria E.,Damora, Angela,Vitagliano, Aldo
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experimental part
p. 5878 - 5884
(2011/02/23)
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- Production of oxetanones
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The invention relates to a novel process for producing a compound having the formula STR1 wherein R1, R2 and X are described herein, via wherein R corresponding β-keto- and β-hydroxy-δ-lactones, as well as novel intermediates which occur in the process.
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- Bromine addition to α-(1-hydroxyalkyl)- and α-(1-alkoxyalkyl)-α,β-unsaturated esters, an approach to hydroxyfimbrolide and bromobeckerelide
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Conventional ionic bromination of electron-poor olefins, 2-(1-hydroxyalkyl)- and 2-(1-alkoxyalkyl)propenoates, 2b-d, and methyl (E)-2-(1-hydroxyethyl)-2-butenoate, 3a, proceeds with yields higher than 80%. Treatment of (E)-3-bromo-2-[1-(2-methoxyethoxy)methoxy]butyl]propenoic acid, 16, with two equivalents of strong bases, reaction related with a possible hydroxyfimbrolide and bromobeckerelide synthesis, resulted in the halogen-metal exchange reaction affording the acrylic acid 18, presumably through the generation of dianion 19.
- Calderon,Font,De March
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p. 5347 - 5358
(2007/10/02)
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- Stereochemical Control in Microbial Reduction. 9. Diastereoselective Reduction of 2-Alkyl-3-oxobutanoate with Bakers' Yeast
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Bakers' yeast reduces esters of 2-alkyl-3-oxobutanoic acid (CH3COCHRCO2R'; R=methyl, ethyl, propyl, propargyl, and allyl) into the corresponding (S)-hydroxy esters with exclusive stereoselectivity, while the configuration at the 2-position of the hydroxy esters is either S (anti) or R (syn) depending on the structure of the alkoxyl group in the carboalkoxyl moeity of the ester.Oftently, the stereoselectivity with respect to the 2-position is not satisfactory.In general, the reduction of t-butyl esters exerts predominancy in the products, whereas that of 1,1-dimethylpropyl esters exerts the syn predominancy.A marked difference between these two esters in diastereoselectivity is dicussed from the view point of plausible conformations of the esters.
- Nakamura, Kaoru,Miyai, Takehiko,Nagar, Ashish,Oka, Shinzaburo,Ohno, Atsuyoshi
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p. 1179 - 1187
(2007/10/02)
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