- Synthesis of 2-hydroxy-3-methyl-2-cyclo-pentenone, corylone, from 2-ketoglutaric acid
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Treatment of 2-ketoglutaric acid with diazomethane gave 2-(methoxycarbonyl)-oxiranepropanoic acid methyl ester (2) which lead to 2-hydroxy-2-methyl-glutaric acid dimethyl ester (3) by catalytic hydrogenation, which was further processed to the title compound.
- Dos Santos,De Magalhaes
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- Synthetic method of methyl cyclopentenolone
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The invention relates to a preparation method of methyl cyclopentenolone, which comprises the following steps: (1) controlling the pH value and temperature of a reaction system, and reacting a dimethylamine hydrochloride, a formaldehyde aqueous solution and 2-methyl furan to generate N, N-dimethyl-5-methyl furfuryl amine; (2) when it is monitored that the content of the 2-methyl furan is not reduced any more, adjusting the pH value of the reaction solution to be less than 1 by using an acid solution, and reacting to obtain a product 1-dimethyl amino-2, 5-hexanedione; and (3) adjusting the pH value of the reaction solution to 12-13 by using an alkali, reacting, extracting the reaction solution, concentrating to recover the solvent, and rectifying to obtain a product 2-(dimethylamino)-3-methyl-2-cyclopentene-1-one; and (4) mixing 2-(dimethylamino)-3-methyl-2-cyclopentene-1-one with hydrochloric acid, reacting, hydrolyzing, crystallizing and purifying to obtain methyl cyclopentenolone, and concentrating and recycling a reaction mother liquor Compared with the prior art, the method has the advantages that remote and automatic operation is facilitated, wastewater treatment is reduced, and the raw material dimethylamine hydrochloride can be reused.
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Paragraph 0015; 0035; 0039-0041; 0045-0047; 0051-0053
(2021/01/15)
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- Green synthesis method of methyl cyclopentenolone
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The invention relates to a green synthesis method of methyl cyclopentenolone, and belongs to the field of organic synthesis. The method comprises the following synthesis steps: A, carrying out Mannichreaction on 2-methyl furan serving as a raw material and piperidine hydrochloride to generate an aminated intermediate; B, adding a catalytic amount of sulfuric acid into the aminated intermediate for reflux reaction to obtain a hydrolysate; and C, adding the hydrolysate into methylbenzene, neutralizing to be neutral by using sodium hydroxide, adding piperidine and pyridine, refluxing and separating water until no water is separated out, and rectifying to obtain a cyclized product; and D, putting the cyclized product into an acetic acid-hydrochloric acid solution for reflux reaction, cooling,removing piperidine hydrochloride, removing acetic acid from the filtrate, adding water, and crystallizing to obtain methyl cyclopentenolone. According to the method, the generation of wastewater andwaste salt is greatly reduced, the generated piperidine hydrochloride can be recycled and reused, and the method is a green synthetic method for synthesizing methyl cyclopentenolone.
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Paragraph 0055-0066
(2020/12/05)
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- Convenient and easy access to 2-hydroxycyclopent-2-enones from acylcyanohydrins
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A convenient access to 2-hydroxycyclopentenones was designed from acylcyanohydrins, by using titanacyclopropane complexes as nucleophilic partners and an intramolecular aldol condensation in basic conditions. The development of a one-pot procedure allows a step- and atom-economic process, and the use of Grignard reagents other than ethylmagnesium bromide provided valuable 3,4-disubstituted 2-hydroxycyclopentenones. The utility of the hydroxy group was illustrated by further functionalization of the α-position using palladium-mediated cross-coupling reactions.
- Pantin, Mathilde,Bodinier, Florent,Saillour, Jordan,Youssouf, Yassine M.,Boeda, Fabien,Pearson-Long, Morwenna S.M.,Bertus, Philippe
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p. 4657 - 4662
(2019/07/16)
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- Cyclopentanone Derivatives from 5-Hydroxymethylfurfural via 1-Hydroxyhexane-2,5-dione as Intermediate
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An efficient strategy for the conversion of biomass derived 5-hydroxymethylfurfural (HMF) into 2-hydroxy-3-methylcyclopent-2-enone (MCP) by an intramolecular aldol condensation of 1-hydroxyhexane-2,5-dione (HHD) has been developed. Further transformations of MCP towards the diol, enol acetate, levulinic acid and N-heterocyclic compounds are also reported.
- Wozniak, Bartosz,Spannenberg, Anke,Li, Yuehui,Hinze, Sandra,de Vries, Johannes G.
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p. 356 - 359
(2018/01/03)
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- Effect of Cp*Iridium(III) Complex and acid co-catalyst on conversion of furfural compounds to cyclopentanones or straight chain ketones
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In this paper, Cp*Ir (III) Complex and acid co-catalyst system was developed. By using Cp*Ir and γ-Al2O3 (Lewis acid), 5-hydroxymethylfurfural (5-HMF) can be converted efficiently to 3-hydroxymethyl cyclopentanone (HCPN). Meanwhile, Cp*Ir and Br?nsted acid can promote conversion of 5-HMF to 1-Hydroxy-2,5-hexanedione (HHD). The effect of Lewis acid and Br?nsted acid on the hydrogenation of furan derivatives was studied. Mechanism of conversion of 5-HMF to HCPN was discussed in detail and mechanism proposed by our predecessors was revised. Instead of being an intermediate for the formation of HCPN, it is believed that, HHD is a product of another reaction pathway. HHD condensed via Aldol reaction to produce 3-methylcyclopenten-2-ol-1-one (MCP) instead of HCPN. Under the promotion of Lewis acid, 5-HMF firstly convert to the precursor of HHD. After that, the reaction is through 4 π-electrocyclic ring closure process and HCPN was formed ultimately. Furthermore, we found that our Cp*Ir and acid co-catalyst system is suitable for a variety of furfural compounds. By using Cp*Ir, Br?nsted acid can promote conversion of furfural compounds to straight chain ketones and Lewis acid can promote the rearrangement of furfural compounds to cyclopentanone derivatives.
- Xu, Yong-Jian,Shi, Jing,Wu, Wei-Peng,Zhu, Rui,Li, Xing-Long,Deng, Jin,Fu, Yao
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p. 266 - 273
(2017/07/13)
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- Conversion of HMF to methyl cyclopentenolone using Pd/Nb2O5 and Ca-Al catalysts: Via a two-step procedure
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The catalytic conversion of HMF to 2-hydroxy-3-methyl-2-cyclopenten-1-one (MCP), which is a valuable edible essence that has traditionally been obtained from adipic acid, was achieved with an isolated yield of 58%. This procedure comprised two steps: the hydrogenation of 5-hydroxymethylfurfural (HMF) to 1-hydroxy-2,5-hexanedione (HHD) in water on Pd/Nb2O5 catalysts and then the isomerization of HHD to MCP in the presence of a base. The Nb2O5 supports, which were acidic, were characterized by FTIR, XRD and NH3-TPD. The supported Pd/Nb2O5 catalysts, in which Pd was highly dispersed, were synthesized employing cyclohexene as a reductant and were characterized by XRD, TEM, ICP-AES, XPS, EDX and CO pulse chemisorption. The high conversion of HMF was attributed to the high dispersion of Pd, and the acidity of the supports led to high selectivity for HHD. The conversion of HHD to MCP was an intramolecular aldol condensation reaction, and the protonic solvent favored this reaction. Ca-Al was proved to be an effective solid base for the conversion of HHD to MCP in water.
- Duan, Ying,Zheng, Min,Li, Dongmi,Deng, Dongsheng,Ma, Lu-Fang,Yang, Yanliang
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p. 5103 - 5113
(2017/11/09)
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- Method of preparing 2-hydroxy-3-methyl-2-cyclopentene-1-one from fructose
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The invention discloses a method of preparing 2-hydroxy-3-methyl-2-cyclopentene-1-one with fructose as a raw material. The method includes the following steps: 1) under a hydrogen atmosphere, performing hydrodeoxygenation to the fructose on a Pd-based hydrogenation catalyst to generate 1-hydroxy-2,5-hexanedione; and 2) performing isomerization to the 1-hydroxy-2,5-hexanedione to prepare the 2-hydroxy-3-methyl-2-cyclopentene-1-one from fructose under an alkali condition. The method only includes two catalytic reactions, is simple in production process and is high in total yield. Water is employed as a solvent in the reactions without usage of any toxic and harmful reagents, so that the method is mild in reaction conditions and is green and environment-friendly. The method is high in yield and is less in side products. The product is convenient to separate and purify.
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Paragraph 0044; 0045
(2017/01/17)
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- Heterogeneous platinum catalytic aerobic oxidation of cyclopentane-1,2- diols to cyclopentane-1,2-diones
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A method for the aerobic oxidation of cyclopentane-1,2-diols to the corresponding diketones over a commercial heterogeneous Pt/C catalyst is described. Unsubstituted and 3- or 4-substituted cyclopentane-1,2-diols are oxidized to 1,2-dicarbonyl compounds in good yields under the reported optimized reaction conditions (atmospheric air, 1 mol % of catalyst, 1 equiv of LiOH, aqueous solvents and 60 °C temperature). The method is applicable for producing cyclopentane-1,2-diketones in a scalable manner.
- Reile, Indrek,Kalle, Sigrid,Werner, Franz,J?rving, Ivar,Kudrjashova, Marina,Paju, Anne,Lopp, Margus
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p. 3608 - 3613
(2014/05/20)
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- Practical preparation of diosphenols by ring opening of α,β-epoxyketones catalyzed by silica gel supported acids
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The mixed acid (H2SO4-HOAc) catalyzed ring opening of α,β-epoxyketone was the most used method for the preparation of diosphenols, but it seriously suffered from poor yields and tedious workup operations. By using silica gel supported mixed acid (H2SO 4-HOAc), a variety of α,β-epoxyketones were converted into the corresponding diosphenols in unprecedented high yields within a few minutes. Georg Thieme Verlag Stuttgart.
- Zhu, Rui,Xing, Lixin,Wang, Xinyan,Cheng, Chuanjie,Liu, Bo,Hu, Yuefei
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p. 2267 - 2271
(2008/02/09)
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- Conversion of α,β-epoxyketones to diosphenols using 6-methyl-2-pyridone anion as an hydroxide equivalent
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Treatment of α,β-epoxyketones with 6-methyl-2-pyridone anion gives diosphenol (6-methyl-2-pyridyl) ethers that can be cleaved to diosphenols under mild basic conditions. (C) 2000 Elsevier Science Ltd.
- Ponaras,Meah
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p. 9031 - 9035
(2007/10/03)
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- Evaluation of acute toxicity and genotoxicity of liquid products from pyrolysis of Eucalyptus grandis wood
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Slow pyrolysis of Eucalyptus grandis wood was performed in an oven laboratory, and smoke was trapped and condensed to yield liquid products. Polycyclic aromatic hydrocarbons (PAHs) and phenolic fractions were isolated from the former liquid products using adsorption column chromatography (ACC) and identified by GC/MS. Concentrations of PAH and phenolic fractions in total pyrolysis liquids were respectively 48.9 μg/g and 8.59% (w/w). Acute toxicity of total samples of pyrolysis liquids and the phenolic fraction was evaluated by means of two bioassays, namely, 24-h immobilization bioassay with Daphnia magna and Microtox(TM) bioassays, the latter employing the luminescent bacteria Photobacterium phosphoreum. Total pyrolysis liquids and the PAH fraction were evaluated for genotoxicity by the Microtox(TM) bioassay conducted using rehydrated freeze-dried dark mutant of the luminescent bacteria Vibrio fisheri strain M169. Total pyrolysis liquids and the phenolic fraction, respectively, in concentrations of 170 and 68 mg/L were able to immobilize 50% (EC50) of the D. magna population following 24-h exposure. Concentrations of 19 and 6 mg/L, respectively, for total pyrolysis liquids and phenolic fraction were the effective concentrations that resulted in a 50% (EC50) reduction in light produced by bacteria in the Microtox(TM) bioassay. Accordingly, the Microtox(TM) bioassay was more sensitive to toxic effects of both kind of samples than the D. magna bioassay, particularly for the phenolic fraction. Regarding to the genotoxicity evaluation, the results achieved by Microtox(TM) bioassay showed that total pyrolysis liquids had no genotoxic effects with and without exogenous metabolic activation using rat liver homogenate (S9). However, the PAH fraction showed toxic effects with rat liver activation and had a dose-response number (DRN) equal to 1.6, being in this way suspected genotoxic. The lowest detected concentration (LDC) of the PAH fraction able to cause genotoxic effects was 375 μg/L.
- Pimenta,Bayona,Garcia,Solanas
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p. 169 - 175
(2007/10/03)
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- Polymer pyrolysis and oxidation studies in a continuous feed and flow reactor: Cellulose and polystyrene
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A dual-zone, continuous feed tubular reactor is developed to assess the potential for formation of products from incomplete combustion in thermal oxidation of common polymers. Solid polymer (cellulose or polystyrene) is fed continuously into a volatilization oven where it fragments and vaporizes. The gas-phase polymer fragments flow directly into a second, main flow reactor to undergo further reaction. Temperatures in the main flow reactor are varied independently to observe conditions needed to convert the initial polymer fragments to CO2 and H2O. Combustion products are monitored at main reactor temperatures from 400 to 850 °C and at 2.0-s total residence time with four on-line GC/FIDs; polymer reaction products and intermediates are further identified by GC/MS analysis. Analysis of polymer decomposition fragments at 400 °C encompasses complex oxygenated and aromatic hydrocarbon species, which range from high-molecular-weight intermediates of ca. 300 amu, through intermediate mass ranges down to C1 and C2 hydrocarbons, CO, and CO2. Approximately 41 of these species are positively identified for cellulose and 52 for polystyrene. Products from thermal oxidation of cellulose and polystyrene are shown to achieve complete combustion to CO2 and H2O at a main reactor temperature of 850 °C under fuel-lean equivalence ratio and 2.0-s reaction time. A dual-zone, continuous feed tubular reactor is developed to assess the potential for formation of products from incomplete combustion in thermal oxidation of common polymers. Solid polymer (cellulose or polystyrene) is fed continuously into a volatilization oven where it fragments and vaporizes. The gas-phase polymer fragments flow directly into a second, main flow reactor to undergo further reaction. Temperatures in the main flow reactor are varied independently to observe conditions needed to convert the initial polymer fragments to CO2 and H2O. Combustion products are monitored at main reactor temperatures from 400 to 850°C and at 2.0-s total residence time with four on-line GC/FIDs; polymer reaction products and intermediates are further identified by GC/MS analysis. Analysis of polymer decomposition fragments at 400°C encompasses complex oxygenated and aromatic hydrocarbon species, which range from high-molecular-weight intermediates of ca. 300 amu, through intermediate mass ranges down to C1 and C2 hydrocarbons, CO, and CO2. Approximately 41 of these species are positively identified for cellulose and 52 for polystyrene. Products from thermal oxidation of cellulose and polystyrene are shown to achieve complete combustion to CO2 and H2O at a main reactor temperature of 850°C under fuel-lean equivalence ratio and 2.0-s reaction time.
- Park, Byung-Ik,Bozzelli, Joseph W.,Booty, Michael R.,Bernhard, Mary J.,Mesuere, Karel,Pettigrew, Charles A.,Shi, Ji-Chun,Simonich, Staci L.
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p. 2584 - 2592
(2007/10/03)
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- Highly chemo- and regioselective rearrangement of α,β-epoxy ketones to 1,3-dicarbonyl compounds in 5 mol dm-3 lithium perchlorate-diethyl ether medium
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Epoxides from α,β-unsaturated ketones undergo highly chemo- and regioselective rearrangement to 1,3-dicarbonyl compounds in 5 mol dm-3 lithium perchlorate-diethyl ether medium by a 1,2-migration of the carbonyl group at ambient conditions. The Royal Society of Chemistry 1999.
- Sankararaman,Ncsakumar
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p. 3173 - 3175
(2007/10/03)
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- On the Role of 2,3-Dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one in the Maillard Reaction
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To investigate the thermal degradation pathways of 2,3-dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one (1) in the Maillard reaction, the 13C-labeled and unlabeled 1 were synthesized and heated in model systems of food processing. The extent and position of the labeling of the reaction products were interpreted by the mass spectroscopy data. The volatiles identified were, among others, 2,4-dihydroxy-2,5-dimethyl-3(2H)-furanone (2), 2,5-dimethyl-4-hydroxy-3(2H)-furanone, cyclotene, maltol, 5-hydroxymaltol, and some acyclic carbonyls. Under roasting conditions, 2 was formed as a major product. It was concluded that 1 might be transferred to highly reactive open-chain intermediates like the enolic forms of 1-deoxyosone. The further reaction pathways varied with the reaction conditions. Possible degradation pathways of 1 that resulted from the labeling experiments as well as the formation of the described products are discussed.
- Kim, Myong-Ock,Baltes, Werner
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p. 282 - 289
(2007/10/03)
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- Acetoacetic acid ester derivatives for the manufacture of α-hydroxycarbonyl compounds
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The invention is concerned with a novel process for the manufacture of compounds of the formula STR1 wherein R1 signifies C1-5 -alkyl, especially methyl, ethyl, propyl or isopropyl, and the radicals R2 each independently represent hydrogen or C1-5 -alkyl, especially hydrogen or methyl, ethyl, propyl or isopropyl. The process is characterized in that a compound of the formula STR2 wherein R stands for C1-4 -alkoxy, chlorine, bromine or C1-4 -alkanoyloxy, R1 and R2 have the above significance and R3 represents C1-4 -alkyl. is hydrolyzed and subjected to an aldol condensation and, where R=C1-4 -alkoxy, the reaction product is subsequently subjected to an acid treatment. The compounds I are for the most part known flavoring substances.
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- Process for preparing cyclopentenone derivatives
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A process for preparing cyclopentenone derivatives represented by the formula: STR1 wherein R1 is methyl or ethyl, and R2 is hydrogen, methyl or acetyl, characterized in that a 1,4-diketone derivative represented by the formula: wherein R1 and R2 are as defined above is cyclized in the presence of a basic catalyst.
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- SYNTHESI OF 2-HYDROXY-3-METHYL-2-CYCLOPENTENONE FROM ISOPRENE
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Pyrolysis of the 1:1 isoprene-dichlorocarbene adduct and pyrolysis of the gem-dichlorocyclopentene gave 3-methyl-2-cyclopentenone which was further processed to the title compound.
- Ho, Tse-Lok,Lui, Shing-Hou
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p. 685 - 690
(2007/10/02)
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- Process for the preparation of alpha-hydroxycarbonyl compounds
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The instant invention provides a new and improved method of preparing α-hydroxycarbonyl compounds, particulary substituted cyclopent-2-en-2-ol-1-ones and substituted 3-hydroxy-2(5H)-furanones. The novel sequence involves a number of novel intermediates including substituted 2-cyanocyclopentanones, substituted 2-cyano-2-hydroxycyclopentanones, and 2-cyano-2-hydroxyvalero-γ-lactones.
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- High yield "one-pot" synthesis of 2-hydroxy-3-methylcyclopent-2-en-1-one and related compounds
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A convenient "one-pot" modification of a conventional synthetic route affords 2-hydroxy-3-methylcyclopent-2-en-1-one and related compounds in high overall yields.
- Strunz, George M.,Lal, G. Sankar
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p. 572 - 573
(2007/10/02)
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- Synthesis 2-alkyl cyclopentenolones
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2-Hydroxy-3-methylcyclopent-2-en-1-one was synthesized in a five-step synthesis starting from 2-methyl-1,3-butadiene. Novel intermediate steps include the hot tube isomerization of 1,1-dihalo-2-methyl-2-vinylcyclopropane to give 1-methyl-4,4-dihalocyclopent-1-ene, hydrolysis to 3-methyl-2-cyclopenten-1-one, epoxidation of the latter using a phase transfer catalyst, followed by catalyzed isomerization to produce 2-hydroxy-3-methylcyclopent-2-en-1-one in high overall yield.
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- ADDITION VON ALDEHYDEN AN AKTIVIERTE DOPPELBINDUNGEN, XXVII. MITTEILUNG : EIN EINFACHER WEG ZU 2-HYROXY-CYCLOPENTENONEN
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A new, easy synthetic route to 2-hydroxy-3-alkyl-cyclopentenones starting from the thiazolium salt catalyzed addition of aldehydes to 1-acetoxy-3-buten-2-one is described.
- Stetter, H.,Schlenker, W.
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p. 3479 - 3482
(2007/10/02)
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- Method of preparing 2-hydroxy-3-alkyl-2-cyclopenten-1-one
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A method of preparing 2-hydroxy-3-alkyl-2-cyclopenten-1-one which comprises reacting 2-alkyl-5-carboalkoxycyclopentanone with nitrite in the presence of water and alkali; rendering the reaction system acidic; and either treating the mass for hydrolysis by heating or carrying out oxime exchange reaction in the presence of an aliphatic lower carbonyl compound added as an acceptor to the acidified reaction system.
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