- Synthetic method of methyl ketone compound
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The invention relates to the technical field of organic synthesis, and provides a synthesis method for a methyl ketone compound. The synthesis method comprises the following steps: mixing terminal alkyne, an organic solvent, an acid and water, and carrying out a hydration reaction to obtain a methyl ketone compound. According to the synthetic method provided by the invention, the use a catalyst containing metal ions and an oxidizing agent can be avoided, the raw materials are directly subjected to the hydration reaction in the presence of acid and water, and the complicated operation of removing metal ions is avoided in the post-treatment process of the produced methyl ketone compound; the method provided by the invention is high in raw material conversion rate and relatively high in product yield and product purity; the synthesis reaction process is simple and convenient to operate, green and environment-friendly, and suitable for large-scale industrial production; the synthetic method provided by the invention is mild in reaction conditions and easy to control. Results of an embodiment of the invention show that when the method is used for preparing the methyl ketone compound, yield can reach 96.4%, and product purity reaches 99.2%.
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Paragraph 0072-0079
(2020/06/16)
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- Diastereo- and regioselective synthesis of diquinanes and related systems from tricyclo[3.3.0.02,4]octanes by chemical electron transfer (CET)
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A new synthetic methodology for diquinanes by one-electron oxidation of tricyclo[3.3.0.02,4]octanes and subsequent stereocontrolled rearrangement is provided. The latter compounds are conveniently accessible through acid-catalyzed isopyrazole cycloaddition, followed by hydrogenation and photoextrusion of molecular nitrogen. The oxidative rearrangement of the tricyclooctanes proceeds catalytically and cleanly to afford regio- and diastereoselectively the corresponding diquinanes.
- Adam,Heidenfelder,Sahin
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p. 1163 - 1170
(2007/10/02)
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- Synthesis and Thermolysis of Ketal Derivatives of 3-Hydroxy-1,2-dioxolanes
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3--3,4,4,5-tetramethyl-5-phenyl-1,2-dioxolane (2), 3-methoxy-3,4,4,5-tetramethyl-5-phenyl-1,2-dioxolane (3), and 3-acetoxy-3,4,4,5-tetramethyl-5-phenyl-1,2-dioxolane (4) were synthesized from the corresponding 3-hydroxy-1,2-dioxolane (1a) under basic conditions. 3-Acetoxy-4,4-dimethyl-3,5,5-triphenyl-1,2-dioxolane (5) was also synthesized via this approach.Under acidic conditions, 3-hydroxy-1,2-dioxolane 1a underwent quantitative decomposition to phenol and 3,3-dimethyl-2,4-pentanedione.This competing degradation was dependent on the nature of the substituents at position-5.Methyl groups at position-5 slowed the degradative rearrangement whereas phenyl groups favored it. 3-Methoxy- and 3-(allyloxy)-4,4,5,5-tetramethyl-3-phenyl-1,2-dioxolanes (6, 7) were synthesized under acidic conditions from the appropriate 1,2-dioxolane precursors and the corresponding alcohols.At 60 deg C, derivatized 1,2-dioxolanes 2-7 were found to be more stable than the corresponding 3-hydroxy-1,2-dioxolanes.The first order rate constants for the thermolysis of 1,2-dioxolanes 2-7 were determined.Product studies showed that thermolysis of 2-5 yielded pairs of ketones and derivatized carboxylic acids.In addition to R-group migration products, an acetoxy migration product was observed for the thermolysis of 4.Thermolysis of 6 at 60 deg C in benzene yielded methyl benzoate and pinacolone, quantitatively.Thermolysis of 7 yielded products analogous to those for 6.No evidence for internal trapping of radicals by the carbon-carbon double bond of the allyloxy group in 7 was found.The thermolysis appeared to proceed with peroxy bond homolysis as the rate-determining step.Subsequent β-scissions of the intermediate 1,5-oxygen diradical with interesting rearrangements that show a high preference for alkyl vs phenyl migration account for the observed product distributions.The results suggest that the β-scission/rearrangement mechanism may not be concerted but rather stepwise to yield 1,3-diradical and carbonyl fragments.
- Baumstark, A. L.,Vasquez, P. C.,Chen, Y.-X.
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p. 6692 - 6696
(2007/10/02)
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- Selective α-Mono- and α,α-Dialkylations of 1,3-Diketones Using Solid Base Prepared from Sodium Ethoxide and Alumina
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The alkylation of 1,3-diketones with alkyl halides using a solid base prepared from sodium ethoxide and alumina was carried out.The amount of 0.4 mol of sodium ethoxide on 50 g of alumina showed by best reactivity for alkylation.Selective mono- and dialky
- Yoshihara, Nobutoshi,Kitagawa, Teruhiro,Ihara, Ikuko,Hasegawa, Sadao,Hasegawa, Tadashi
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p. 1185 - 1187
(2007/10/02)
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- A Study on m-Chloroperbenzoic Acid and Lead Tetraacetate Oxidation of some 1-Aroyl-4,5-dihydro-4,4-dimethyl-5-methylene-1H-pyrazoles
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1-Aroyl-4,5-dihydro-5-methylene-1H-pyrazoles 1 are converted upon oxidation with m-chloroperbenzoic acid to the pyrazolones 2.The same aroyl enamides 1 are also oxidized with LTA to form the acetoxy derivatives 7 and 8.The reaction mechanisms are discussed.
- Mitkidou, Sophia,Stephanidou-Stephanatou, Julia
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- Synthesis of 4,4-Dimethyl-3,4-dihydro-3,3,5-trisubstituted-2H-pyrazoles and N-Benzoyl Derivatives: Method for "Hydrolysis" of Unreactive Amides and Carbamates
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Addition of organolithium reagents to 4,4-dimethyl-3,5-disubstituted-4H-pyrazoles produced a series of 4,4-dimethyl-3,4-dihydro-3,3,5-trisubstituted-2H-pyrazoles, 2-6, in good yield.The reaction was stereoselective: addition of organolithium compounds occurred only to carbon-3 of 4,4-dimethyl-3-alkyl-5-aryl-4H-pyrazoles.The 3,4-dihydro-2H-pyrazoles were found to be of high sensitivity to oxygen.For long term storage and ease of handling, N-benzoyl derivatives were synthesized.Removal of protecting group could not be accomplished by use of many standard sets of conditions.Deprotection was accomplished in high yield by reaction of the N-benzoyl-4,4-dimethyl-3,4-dihydro-3,3,5-trisubstituted-2H-pyrazoles with anhydrous potassium t-butoxide in toluene in the presence of a phase transfer catalyst (18-Crown-6).Cleavage of a N-carbamate derivative was also achieved by this phase transfer approach.This methodology should be applicable to the hydrolysis of unreactive amides and carbamates in general.
- Baumstark, Alfons L.,Choudhary, Anil,Vasquez, Pedro C.,Dotrong, My
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p. 291 - 294
(2007/10/02)
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- Convenient, High-Yield Method for the Methylation of 1,3-Diketones
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A general method for the facile dimethylation of 1,3-diketones is presented.The method involves the use of readily available, inexpensive reagents and is carried out under mild conditions.Monomethylation may be carried out by slight modification (simplification) of the procedure.Several examples are presented which show that the method is applicable to alkylations with primary halides as well.Isolated yields for monoalkylation are approximately 95percent while those for dialkylation are ca. 90percent.Alkylation is taking place by the reaction of the enolates of 1,3-diketones with alkyl halides.
- Choudhary, Anil,Baumstark, Alfons L.
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p. 688 - 690
(2007/10/02)
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- Acylation of Ketone Silyl Enol Ethers with Acid Chlorides. Synthesis of 1,3-Diketones
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Trimethylsilyl enol ethers of ketones are acylated by a variety of acid chlorides in the presence of zinc chloride or antimony trichloride.The major product of this reaction is the 1,3-diketone resulting from C-acylation.Some O-acylation is observed in most cases.Yields of 1,3-diketones varied but were usually good to excellent.
- Tirpak, Robin E.,Rathke, Michael W.
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p. 5099 - 5102
(2007/10/02)
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- Selenium-Sulfur Analogs 2. Synthesis and Characterization of 4-Aralkyl-1,2,3-selenadiazoles and -1,2,3-Thiadiazoles
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The 1,3-diketones 5 and 8 were alkylated with methyl iodide to give the nonenolizable diketones 6 and 9 which condensed with semicarbazide hydrochloride yielding the monosemicarbazones 7 and 10.Cyclization with selenous acid or with thionyl chloride led t
- Hanson, Robert N.,Davis, Michael A.
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p. 1245 - 1247
(2007/10/02)
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