- A 3 - halogenated tetrahydrofuran preparation method
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The invention discloses a 3 - halogenated tetrahydrofuran preparation method. The method comprises the following steps: in the organic solvent, 0 - 85 °C temperature, shown in formula I compound with a reducing agent, can be; wherein R1 And R2 The same, they are selected from chlorine or bromine; the reducing agent is sodium borohydride or potassium borohydride; wherein the organic solvent is b [...], 2 - chloroethyl methyl ether, ethyl ether, tetrahydrofuran or methyl tetrahydrofuran. The method of the invention less reaction steps, the process is simple, the product yield can reach 80% - 95%, and the low cost of raw materials, equipment investment, the price of the product there are advantages; in addition the method pollution is small, friendly to the environment, and is suitable for large-scale industrial production.
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Paragraph 0032; 0033; 0034; 0035; 0036; 0037; 0038-0067
(2019/05/28)
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- Preparation method of 3-aminomethyl tetrahydrofuran
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The invention relates to a preparation method of 3-aminomethyl tetrahydrofuran. Specifically the invention relates to a method of preparing 3-aminomethyl tetrahydrofuran through reducing 3-cyanotetrahydrofuran. A novel synthesis technology is adopted; gamma-butyrolactone and a halogen simple substance X2 are taken as the raw materials to prepare 3-X-gamma-butyrolactone; then 3-X-gamma-butyrolactone is reduced by a reducing agent to obtain 2-X-1,4-butylene glycol; 2-X-1,4-butylene glycol is dehydrated by a dehydrating agent to obtain 3-X tetrahydrofuran; 3-X tetrahydrofuran is converted into 3-cyanotetrahydrofuran in the presence of a cyaniding catalyst, and finally 3-cyanotetrahydrofuran is converted into 3-aminomethyl tetrahydrofuran in the presence of a hydrogenation catalyst. The synthesis technology has the advantages of easily available raw materials, simple operation, mild reaction conditions, high yield and product purity, little environmental pollution, and low production cost, is suitable for industrial massive production, and has a wide application prospect.
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Paragraph 0022; 0029-0031
(2017/07/12)
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- METHOD FOR PRODUCING 3-AMINOMETHYLTETRAHYDROFURAN DERIVATIVE
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An object of the present invention is to provide a process for producing a 3-cyanotetrahydrofuran derivative in a high yield from inexpensive industrial materials. According to the present invention, a 3-aminomethyltetrahydrofuran derivative is produced by preparing a 3-cyanotetrahydrofuran derivative in a high yield from an inexpensive and industrially easily available malic acid derivative, and reducing the cyano group of the 3-cyanotetrahydrofuran derivative.
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- METHOD FOR PRODUCING 3-AMINOMETHYLTETRAHYDROFURAN DERIVATIVE
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Disclosed is a method for highly efficiently producing a 3-aminomethyltetrahydrofuran derivative from a low-cost industrial raw material. Specifically, a 3-cyanotetrahydrofuran derivative is produced at high yield from a low-cost, industrially easily-available malic acid derivative, and then a 3-aminomethyltetrahydrofuran derivative is produced by reducing the cyano group of the 3-cyanotetrahydrofuran derivative.
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Page/Page column 34
(2008/06/13)
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- Introduction of bromine and chlorine substituents in medium ring ethers and lactones
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A convenient preparation of α-halo enamines using oxalyl halides is described together with applications of these reagents in the halogenation of β-hydroxy cyclic ethers and lactones.
- Bendall, Justin G.,Payne, Andrew N.,Screen, Thomas E. O.,Holmes, Andrew B.
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p. 1067 - 1068
(2007/10/03)
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- β-Halogeno Ether Synthesis of Olefinic Alcohols: Stereochemistry and Conformation of 2-Substituted 3-Halogenotetrahydro-pyran and furan Precursors
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Ring-scission of cis- or trans-2-alkyl- (or aryl-) 3-chlorotetrahydropyrans proceeds regioselectively and highly stereoselectively to give (E)-alk-4-en-1-ols, but in the parallel tetrahydrofuran series (Z)-/(E)-mixtures, dependent on percursor geometry, are formed.In this paper the stereochemistry and conformation of the tetrahydro-pyran and - furan precursors are considered.The cis/trans-composition of 2,3-dihalogenotetrahydro-pyrans and-furans made by various routes is reported.Reaction with Grignard reagents gives separable cis-/trans-mixtures the stereoisomeric composition of which, in the cases examined, does not depend on the stereoisomeric composition of the dihalide, but does vary with the halogen and the composition of the Grignard or dialkylmagnesium; possible reasons are discussed.The stereochemistry and conformation of the 2-alkyl- (or aryl-)3-chlorotetrahydropyrans is analysed by n.m.r. methods (J2a,3acis ca. 1.5 Hz; J2a,3atrans ca. 9.8 Hz) but assignments for the two tetrahydrofuran series with J2,3 2.6-3.6 and 4.3-5.9 are made uncertain by pseudorotation.The stereochemical identity of the two series is rigorously proved by isolation of cis- and trans-2-allyl-3-chlorotetrahydrofuran.On the one hand the former is hydrogenated to the cis-2-propyl compound, correlated with other members of the alkyl series, but on the other it is oxidised and the acid is converted into the cis-p-bromophenyl ester.The stereochemistry and conformation of the latter is rigorously demonstrated by an X-ray structure.The stereochemistries and conformations of the 2-deuterio- and 2-methoxy-3-chlorotetrahydropyrans are discussed, and consideration is then extended to the 2-alkyl-3-chloro-2-methyltetrahydro-pyran and -furan series.
- Crombie, Leslie,Wyvill, Robert D.
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p. 1971 - 1982
(2007/10/02)
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