- Diatomite Stabilized KOH: An Efficient Heterogeneous Catalyst for Cyclopentanone Self-condensation
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Aldol condensation of cyclopentanone is an attractive reaction for bio-jet fuel production. KOH is an efficient homogeneous catalyst for aldol condensation but suffering the problem of separation. In this paper, a heterogeneous catalyst, diatomite stabilized KOH (KOH/diatomite) was prepared in a simple way (dry-mixed impregnation process), and exhibited good activity (overall yield: 85.0 %) and reusability. To clarify the support effect of diatomite, KOH/SiO2 catalyst was also prepared. According to characterizations of these two catalysts, we suggest that the excellent catalytic activity of KOH/diatomite can be attributed to the formation of K?O?Si bond. In addition, the impurity elements existed in diatomite (e. g. CaO, Na2O, Al2O3) and higher BET surface areas may also benefit to this reaction. This study provides a new possibility for converting homogeneous catalyst (KOH) to heterogeneous catalyst (KOH/diatomite). In this way, KOH/diatomite performed excellent catalytic activity and exhibited stable reusability, which can avoid the problem of separation and pollution.
- Xu, Qianqian,Sheng, Xueru,Jia, Haiyuan,Li, Na,Zhang, Jian,Shi, Haiqiang,Niu, Meihong,Ping, Qingwei
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Read Online
- Fine-Bubble-Slug-Flow Hydrogenation of Multiple Bonds and Phenols
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We describe a promising method for the continuous hydrogenation of alkenes or alkynes by using a newly developed fine-bubble generator. The fine-bubble-containing slug-flow system was up to 1.4 times more efficient than a conventional slug-flow method. When applied in the hydrogenation of phenols to the corresponding cyclohexanones, the fine bubble-slug-flow method suppressed over-reduction. As this method does not require the use of excess gas, it is expected to be widely applicable in improving the efficiency of gas-mediated flow reactions.
- Iio, Takuya,Nagai, Kohei,Kozuka, Tomoki,Sammi, Akhtar Mst,Sato, Kohei,Narumi, Tetsuo,Mase, Nobuyuki
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supporting information
p. 1919 - 1924
(2020/11/09)
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- Synthesis of Unsaturated Spiroacetals, Cyclopentanone Derivatives, in the Presence of Natural Aluminosilicate Modified with Zirconium Cations
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Abstract: Conditions for the condensation of cyclopentanone and n-valeric aldehyde to 2-pentylidenecyclopentanone in the presence of an alcoholic solution of piperidine have been developed. The isomerization of the latter in a continuous-flow system over γ-Al2O3 yields 2-pentylcyclopent-2-en-1-one. The condensation of the obtained unsaturated ketones with ethane-1,2-diol in the presence of a heterogeneous catalyst, a natural aluminosilicate (perlite) modified with zirconyl sulfate, has been studied. The optimum conditions for the preparation of the corresponding unsaturated spiroacetals have been found. The synthesized compounds can be used as synthetic fragrances for different purposes.
- Abbasov,Alimardanov, Kh. M.,Abbaszade,Guseinova,Azimli
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p. 603 - 607
(2019/06/24)
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- Morphology-Tuned Activity of Ru/Nb2O5 Catalysts for Ketone Reductive Amination
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Amines are important compounds in natural products and medicines. Specifically, cyclopentylamine is one of the value-added chemicals widely used in the production of pesticides, cosmetics and medicines. In this work, three Ru/Nb2O5 catalysts with different Nb2O5 morphologies were used in the reductive amination of cyclopentanone under mild reaction conditions (90 °C, 2 MPa H2), among which 1 %Ru/Nb2O5?L catalyst exhibits best performance with the yield of cyclopentylamine reaching 84 %. This catalytic system is stable and has not significant deactivation even after 5 runs in the durability test. In addition, this catalyst can be extended to a series of aldehydes/ketones. Further comprehensive characterizations (XPS analysis and CO-adsorption DRIFT) reveal that the electronic effect of Ru species can be ruled out; instead, the activity of the catalyst is strongly influenced by the geometric effect. Layered Nb2O5 material possesses the highest surface area, resulting in the highest Ru dispersion, and therefore shows the highest catalytic activity. The in-situ DRIFT-MS technique was also used to reveal and understand the reaction mechanism. It is found that Ru species play a key role in activating carbonyl groups. This study illustrates a promising application of Ru/Nb2O5-Layer catalyst in the synthesis of amine and provides an understanding to the reaction mechanism.
- Guo, Wanjun,Tong, Tao,Liu, Xiaohui,Guo, Yong,Wang, Yanqin
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p. 4130 - 4138
(2019/05/24)
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- Highly efficient Nb2O5 catalyst for aldol condensation of biomass-derived carbonyl molecules to fuel precursors
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Aldol condensation is of significant importance for the production of fuel precursors from biomass-derived chemicals and has received increasing attention. Here we report a Nb2O5 catalyst with excellent activity and stability in the aldol condensation of biomass-derived carbonyl molecules. It is found that in the aldol condensation of furfural with 4-heptanone, Nb2O5 has obviously superior activity, which is not only better than that of other common solid acid catalysts (ZrO2 and Al2O3), more importantly, but also better than that of solid base catalysts (MgO, CaO, and magnesium-aluminum hydrotalcite). The detailed characterizations by N2 sorption/desorption, NH3-TPD, Py-FTIR and DRIFTS study of acetone adsorption reveal that Nb2O5 has a strong ability to activate the C=O bond in carbonyl molecules, which helps to generate a metal enolate intermediate and undergo the nucleophilic addition to form a new C–C bond. Furthermore, the applicability of Nb2O5 to aldol condensation is extended to other biomass-derived carbonyl molecules and high yields of target fuel precursors are obtained. Finally, a multifunctional Pd/Nb2O5 catalyst is prepared and successfully used in the one-pot synthesis of liquid alkanes from biomass-derived carbonyl molecules by combining the aldol condensation with the sequential hydrodeoxygenation.
- Jing, Yaxuan,Xin, Yu,Guo, Yong,Liu, Xiaohui,Wang, Yanqin
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p. 1168 - 1177
(2019/07/09)
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- Thermal Degradation of Aviation Synthetic Lubricating Base Oil
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The thermal degradation, under oxidative pyrolysis conditions, of two synthetic lubricating base oils, poly-α-olefin (PAO) and di-ester (DE), was investigated. The main objective of the study was to characterize their behavior in simulated “areo-engine” conditions, i.e. compared the thermal stability and identified the products of thermal decomposition as a function of exposure temperature. Detailed characterizations of products were performed with Fourier transform infrared spectrometry (FTIR), gas chromatography/ mass spectrometry (GC/MS), viscosity experiments and four-ball tests. The results showed that PAO had the lower thermal stability, being degraded at 200°C different from 300°C for DE. The degradation also effected the tribological properties of lubricating oil. Several by-products were identified during the thermal degradation of two lubricants. The majority of PAO products consisted of alkanes and olefins, while more oxygen-containing organic compounds were detected in DE samples according to the observation of GC/MS analysis. The related reaction mechanisms were discussed according to the experimental results.
- Wu, Nan,Zong, Zhimin,Fei, Yiwei,Ma, Jun,Guo, Feng
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p. 250 - 257
(2018/04/09)
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- Simultaneous Upgrading of Furanics and Phenolics through Hydroxyalkylation/Aldol Condensation Reactions
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The simultaneous conversion of cyclopentanone and m-cresol has been investigated on a series of solid-acid catalysts. Both compounds are representative of biomass-derived streams. Cyclopentanone can be readily obtained from sugar-derived furfurals through Piancatelli rearrangement under reducing conditions. Cresol represents a family of phenolic compounds, typically obtained from the depolymerization of lignin. In the first biomass conversion strategy proposed here, furfural is converted in high yields and selectivity to cyclopentanone (CPO) over metal catalysts such as Pd-Fe/SiO2 at 600 psi (~4.14 MPa) H2 and 150 °C. Subsequently, CPO and cresol are further converted through acid-catalyzed hydroxyalkylation. This C?C coupling reaction may be used to generate products in the molecular weight range that is appropriate for transportation fuels. As molecules beyond this range may be undesirable for fuel production, a catalyst with a suitable porous structure may be advantageous for controlling the product distribution in the desirable range. If Amberlyst resins were used as a catalyst, C12–C24 products were obtained whereas when zeolites with smaller pore sizes were used, they selectively produced C10 products. Alternatively, CPO can undergo the acid-catalyzed self-aldol condensation to form C10 bicyclic adducts. As an illustration of the potential for practical implementation of this strategy for biofuel production, the long-chain oxygenates obtained from hydroxyalkylation/aldol condensation were successfully upgraded through hydrodeoxygenation to a mixture of linear alkanes and saturated cyclic hydrocarbons, which in practice would be direct drop-in components for transportation fuels. Aqueous acidic environments, which are typically encountered during the liquid-phase upgrading of bio-oils, would inhibit the efficiency of base-catalyzed processes. Therefore, the proposed acid-catalyzed upgrading strategy is advantageous for biomass conversion in terms of process simplicity.
- Bui, Tuong V.,Sooknoi, Tawan,Resasco, Daniel E.
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p. 1631 - 1639
(2017/04/14)
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- Base-promoted ring expansion of 3-aminopyrimidine-2-thiones into 1,2,4-triazepine-3-thiones
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A base-promoted ring expansion of 3-amino-4-hydroxyhexahydropyrimidine-2-thiones into 2,4,5,6-tetrahydro-3H-1,2,4-triazepine-3-thiones has been developed. Experimental data and DFT calculations showed that the reaction proceeded through fast formation of intermediate acyclic isomers of pyrimidines followed by their slow cyclization into triazepines. The starting hydroxypyrimidines were prepared by reaction of α,β-unsaturated ketones or β-alkoxy ketones with HNCS followed by treatment of the obtained β-isothiocyanato ketones with hydrazine. Triazepine-3-thiones were transformed into their 3-oxo analogs by oxidation with H2O2 under basic conditions.
- Fesenko, Anastasia A.,Shutalev, Anatoly D.
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p. 2560 - 2573
(2016/04/26)
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- Towards quantitative and scalable transformation of furfural to cyclopentanone with supported gold catalysts
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Given the vital importance of furfural (FFA) upgrading towards a sustainable bio-based economy, an eco-friendly aqueous route to produce a sole valuable product from FFA is highly desirable. We herein describe an efficient approach to quantitatively convert FFA into cyclopentanone (CPO) in neat water, employing H2 as the clean reductant and supported gold nanoparticles as a simple yet versatile catalyst. The use of anatase TiO2 featuring only mild Lewis acidic sites as the underlying support is essential, not only for preventing undesirable side reactions, but also for attaining high CPO selectivity. The feasibility of using biogenic CPO and CO2 as benign carbon sources to synthesize the industrially important feedstock dimethyl adipate is also demonstrated.
- Zhang, Gao-Shuo,Zhu, Ming-Ming,Zhang, Qi,Liu, Yong-Mei,He, He-Yong,Cao, Yong
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p. 2155 - 2164
(2016/04/19)
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- Controllable self-aldol condensation of cyclopentanone over MgO-ZrO2 mixed oxides: Origin of activity & selectivity
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Mesoporous MgO-ZrO2 mixed oxides with different Mg/Zr ratios have been synthesized by a coprecipitation method and employed to catalyze self-aldol condensation of cyclopentanone in a solvent-free condition under atmospheric pressure. Effects of temperature, reaction time, catalyst amount and Mg/Zr ratio on the reaction have been investigated. Remarkable raise in catalytic activity and selectivity has been found on MgO-ZrO2 mixed oxides as compared with pure MgO or ZrO2. Characterization including XRD, XPS, BET and CO2- TPD has been carried out to figure out the relationship between catalyst properties and their catalytic activity.
- Liang, Decheng,Li, Guozhu,Liu, Yanhong,Wu, Jinmeng,Zhang, Xiangwen
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- Direct conversion of carboxylic acids (Cn) to alkenes (C2n - 1) over titanium oxide in absence of noble metals
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Carbon-carbon bond formations and deoxygenation reactions are important for biomass up-grading. The classical ketonic decarboxylation of carboxylic acids provides symmetrical ketones with 2n + 1 carbon atoms and eliminates three oxygen atoms. Herein, this reaction is carried out with titanium oxide at 400°C, and an olefin with 2n + 1 carbon atoms is obtained instead of the ketone. For olefin formation hydrogen transfer reactions are required from suitable precursors to form aromatics and coke. Additional aldol condensation reactions increase further molecular weight in the product mixture. Hence, a combination of titanium oxide with a hydrodeoxygenation bed provides double amount of diesel fuel as the combination with zirconium oxide when reacting hexose-derived pentanoic acid.
- Oliver-Tomas, Borja,Renz, Michael,Corma, Avelino
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- Highly selective self-condensation of cyclic ketones using MOF-encapsulating phosphotungstic acid for renewable high-density fuel
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Transferring biomass-derived cyclic ketones such as cyclopentanone and cyclohexanone to a mono-condensed product through aldol self-condensation has great potential for the synthesis of a renewable high-density fuel. However, the selectivity is low for numerous catalysts due to the rapid formation of di-condensed by products. Herein, MIL-101-encapsulating phosphotungstic acid is synthesized to catalyze the self-condensation with selectivity of more than 95%. PTA clusters are uniformly dispersed in MOF cages and decrease the empty space (pore size), which provides both acidic sites and shape-selective capability. The optimal PTA amount decreases corresponding to the increase of reactant size. The shape-selectivity is also realized by changing the pore size of MOF such as from MIL-101 to MIL-100. Moreover, the catalyst is resistant to PTA leaching and performs stably after 5 runs. After hydrodeoxygenation of the mono-condensed product, high-density biofuels with densities of 0.867 g ml-1 and 0.887 g ml-1 were obtained from cyclopentanone and cyclohexanone, respectively. This study not only provides a promising route for the production of high-density biofuel but also suggests the advantage of MOF-based catalysts for shape-selective catalysis involving large molecular size.
- Deng, Qiang,Nie, Genkuo,Pan, Lun,Zou, Ji-Jun,Zhang, Xiangwen,Wang, Li
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p. 4473 - 4481
(2015/08/11)
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- Synthesis of renewable high-density fuels using cyclopentanone derived from lignocellulose
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By the combination of solvent-free aldol condensation and one-step hydrodeoxygenation under mild reaction conditions, a high-density (0.866 g mL-1) bicyclic C10 hydrocarbon was synthesized in high overall yield (up to 80%) using cyclopentanone derived from lignocellulose. The Royal Society of Chemistry 2014.
- Yang, Jinfan,Li, Ning,Li, Guangyi,Wang, Wentao,Wang, Aiqin,Wang, Xiaodong,Cong, Yu,Zhang, Tao
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supporting information
p. 2572 - 2574
(2014/03/21)
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- Iodine-catalyzed cycloalkenylation of dihydroquinolines and arylamines through a reaction with cyclic ketones under neat conditions
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An iodine-catalyzed direct cycloalkenylation of dihydroquinolines and arylamines has been developed. This method consists of a Friedel-Crafts reaction between dihydroquinolines (or arylamines) and cyclic ketones in which the double bond is selectively generated throughout the course of the reaction resulting in a direct cycloalkenylation, under neat conditions.
- Fotie, Jean,Ayer, Suraj K.,Poudel, Binit S.,Reid, Carolyn S.
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supporting information
p. 7069 - 7073
(2013/12/04)
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- Conversion of furfural into cyclopentanone over Ni-Cu bimetallic catalysts
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The conversion of furfural into cyclopentanone over Ni-Cu bimetallic catalysts was studied under hydrogen atmosphere. Furfuryl alcohol, 4-hydroxy-2-cyclopentenone and 2-cyclopentenone were verified as three key intermediates. Rearrangement of the furan ring was independent of hydrogenation, starting from furfuryl alcohol rather than furfural. The opening and closure of the furan ring were closely related to the attack of a H2O molecule on the 5-position of furfuryl alcohol. Prior hydrogenation of the aldehyde group accounted for the different reactivity of furfural and furfuryl alcohol. The high selectivity of cyclopentanone was ascribed to the presence of 2-cyclopentenone.
- Yang, Yanliang,Du, Zhongtian,Huang, Yizheng,Lu, Fang,Wang, Feng,Gao, Jin,Xu, Jie
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p. 1932 - 1940
(2013/09/24)
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- Nanoporous metal oxides with tunable and nanocrystalline frameworks via conversion of metal-organic frameworks
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Nanoporous metal oxide materials are ubiquitous in the material sciences because of their numerous potential applications in various areas, including adsorption, catalysis, energy conversion and storage, optoelectronics, and drug delivery. While synthetic
- Kim, Tae Kyung,Lee, Kyung Joo,Cheon, Jae Yeong,Lee, Jae Hwa,Joo, Sang Hoon,Moon, Hoi Ri
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supporting information
p. 8940 - 8946
(2013/07/26)
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- Cerium metal-mediated Reformatsky-type reaction with ethyl bromosuccinate for the synthesis of novel paraconic acid analogs
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The treatment of cerium metal with ethyl bromosuccinate (1) forms the stabilized organolanthanoid intermediate (2), which reacts with carbonyl compounds in a Reformatsky-type reaction, under mild conditions, to produce functionalized γ-substituted paraconic acids (4) in good yields.
- Rodrigues, Shirley M. M.,Nardini, Viviani,Constantino, Mauricio G.,Da Silva, Gil Valdo J.
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supporting information
p. 6136 - 6137,2
(2020/08/20)
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- Synthesis of dimethyl adipate from cyclopentanone and dimethyl carbonate over solid base catalysts
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A facile route for the synthesis of dimethyl adipate (DAP) from cyclopentanone and dimethyl carbonate (DMC) in the presence of solid base catalysts has been developed. It was found that the intermediate carbomethoxycyclopentanone (CMCP) was produced from cyclopentanone with DMC in the first step, and then CMCP was further converted to DAP by reacting with a methoxide group. The role of the basic catalysts can be mainly ascribed to the activation of cyclopentanone via the abstraction of a proton in the α-position by base sites, and solid bases with moderate strength, such as MgO, favor the formation of DAP.
- Wu, Dudu,Chen, Zhi,Jia, Zhenbin,Shuai, Li
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experimental part
p. 380 - 385
(2012/10/07)
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- Unexpected 5,6,7,8,9,10-hexahydro-6,6-pentamethylenephenanthridines and 2,3,4,5-tetrahydro-4,4-tetramethylene-1 H -cyclopenta[ c ]quinolines from skraup-doebner-von miller quinoline synthesis and their implications for the mechanism of that reaction
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The real mechanism of the Skraup-Doebner-Von Miller quinoline synthesis remains controversial and not well understood despite several mechanistic studies reported on the matter. A series of unexpected and unusual 5,6,7,8,9,10-hexahydro-6,6-pentamethylenephenanthridines and 2,3,4,5-tetrahydro-4,4-tetramethylene-1H-cyclopenta[c]quinolines have been obtained through the Skraup-Doebner-Von Miller quinoline synthesis. On the basis of these unexpected results and in agreement with some of the previously reported quinoline syntheses, an alternative mechanistic pathway is proposed for this variant of the reaction. It involves the formation of a Schiff base through a reaction between the ketone and the aniline derivative in the first step, followed by a cycloalkenylation at the ortho-position to the amine functional group of the aniline derivative, and an annulation in the final step to close the quinoline ring, leading to a dihydroquinoline derivative. To the best of our knowledge, this is the first report of such a mechanistic pathway being proposed for any variant of the Skraup-Doebner-Von Miller quinoline synthesis.
- Fotie, Jean,Kemami Wangun, Hilaire V.,Fronczek, Frank R.,Massawe, Nancy,Bhattarai, Bijay T.,Rhodus, Jessica L.,Singleton, Thomas A.,Bohle, D. Scott
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experimental part
p. 2784 - 2790
(2012/05/20)
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- A selective solvent-free self-condensation of carbonyl compounds utilizing microwave irradiation
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An environmentally benign microwave-assisted solvent-free self-condensation of carbonyl compounds was developed using catalytic amounts of triethylamine and lithium perchlorate. Changing the amount of lithium perchlorate helps in controlling the ratio of the single-condensation and double-condensation products. The effect of other additives and microwave activation was also investigated. The optimized conditions were then applied to various cyclic/acyclic ketones and aldehydes, with selectivity observed in many cases.
- Sharma, Lalit Kumar,Kim, Kyung Bo,Elliott, Gregory I.
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supporting information; experimental part
p. 1546 - 1549
(2011/07/31)
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- Organocatalytic synthesis of 1,2,3-triazoles from unactivated ketones and arylazides
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Organo-click reaction: A new and complementary method to Huisgen's metal-catalyzed triazole synthesis is described using unactivated ketones and arylazides as the substrates and proline as an organocatalyst. Dramatic acceleration was observed for this reaction using microwave activation and high regio- and chemoselectivities were obtained for a wide range of ketones and arylazides (see scheme). Copyright
- Belkheira, Mokhtaria,El Abed, Douniazad,Pons, Jean-Marc,Bressy, Cyril
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scheme or table
p. 12917 - 12921
(2011/12/04)
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- Catalytic transfer hydrogenation of cycloalkanones on MgO. Vapour and liquid phase modes of reaction
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The reactivity of a series of cycloalkanones of the general formula (CH2)nCO, where n = 4, 5, 6, 7, 11 and 14 in the transfer hydrogenation reaction over magnesium oxide as the catalyst, either in vapour or liquid phase (VP or LP) has been studied. In the VP mode of reaction the activity of MgO treated with triethylamine, water, phenol or benzoic acid in the reduction of cyclopentanone by propan-2-ol has been determined. A strongly diminished or residual activity of MgO has been observed after the catalyst's treatment with phenol or benzoic acid, respectively. The occurrence of side reactions of cyclopentanone in the LP mode of reaction resulted in high conversions of the ketone (up to 91%), very low yields of cyclopentanol (I) (below 6%) and very high yields of 2-cyclopentyli- dene-cyclopentanone (II) (>80%).
- Glinski
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experimental part
p. 187 - 194
(2009/10/23)
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- The palladium-catalyzed aerobic kinetic resolution of secondary alcohols: Reaction development, scope, and applications
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The first palladium-catalyzed enantioselective oxidation of secondary alcohols has been developed, utilizing the readily available diamine (-)-sparteine as a chiral ligand and molecular oxygen as the stoichiometric oxidant. Mechanistic insights regarding the role of the base and hydrogen-bond donors have resulted in several improvements to the original system. Namely, addition of cesium carbonate and tert-butyl alcohol greatly enhances reaction rates, promoting rapid resolutions. The use of chloroform as solvent allows the use of ambient air as the terminal oxidant at 23°C, resulting in enhanced catalyst selectivity. These improved reaction conditions have permitted the successful kinetic resolution of benzylic, allylic, and cyclopropyl secondary alcohols to high enantiomeric excess with good-toexcellent selectivity factors. This catalyst system has also been applied to the desymmetrization of meso-diols, providing high yields of enantioenriched hydroxyketones.
- Ebner, David C.,Bagdanoff, Jeffrey T.,Ferreira, Eric M.,McFadden, Ryan M.,Caspi, Daniel D.,Trend, Raissa M.,Stoltz, Brian M.
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supporting information; experimental part
p. 12978 - 12992
(2010/06/19)
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- Amine-catalyzed aldol condensation in the presence of lithium perchlorate
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A catalytic aldol condensation in the presence of lithium perchlorate and tertiary amines is described giving pure products in high yields. The aldol condensation can be performed even in the presence of hydrated lithium perchlorate. Georg Thieme Verlag Stuttgart.
- Arnold, Aline,Markert, Morris,Mahrwald, Rainer
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p. 1099 - 1102
(2007/10/03)
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- A novel aromatic alkylation of anilines with cyclic and acyclic ketones under hydrothermal conditions
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A novel aromatic ring-alkylation was achieved by condensation between aniline-HCl salts and cyclic or acyclic ketones under hydrothermal conditions.
- Mehta, Barun K.,Kumamoto, Koji,Yanagisawa, Kazumichi,Kotsuki, Hiyoshizo
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p. 6953 - 6956
(2007/10/03)
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- Process for producing 2-bromocyclopentanone
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There is provided a process for producing 2-bromocyclopentanone which process is characterized in that cyclopentanone is reacted with bromine in a biphasic mixture of water and an organic solvent.
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Page column 4
(2008/06/13)
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- Condensation of ketones in the presence of titanium alkoxides
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Titanium alkoxides promote successful condensation of aromatic and aliphatic ketones provided that the liberated alcohol is selectively removed from the reaction mixture.
- Yatluk,Sosnovskikh,Suvorov
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p. 763 - 765
(2007/10/03)
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- Trisannelated benzene synthesis by copper(II) chloride
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Different ketones such as cyclohexanone, cyclopentanone, acetophenone, 2-acetonaphthalene, 4-methylcyclohexanone in the presence of anhydrous CuCl 2 (catalytic amounts) at reflux condition for 2-4 hours, without using a solvent led to dimers 2-(1-cyclohexane-1-yl)-cyclohexanone 6, 2-cyclopentylidene cyclopentanone 10, trimer dodecahydrotriphenylene (DTP) 4, trindan (tricyclopentabenzene) 9,1,3,5-triphenylbenzene (TBP) 12a, 1,3,5-triss-naphthylbenzene 12b and dodecahydro-2,6,10- trimethyltriphenylenes 17 and 18.
- Mahmoodi, Nosrat O.,Hajati, Nezam
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- Cytotoxic 1,4-bis(2-oxo-1-cycloalkylmethylene)benzenes and related compounds
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A series of 1,4-bis(2-oxo-1-cycloalkylmethylene)benzenes 2a-c and 4 and a related acyclic analogue 6a were synthesised and converted to the corresponding Mannich bases 3a-c, 5 and 6b. Evaluation of these compounds against murine P388 and L1210 cells as well as human Molt 4/C8 and CEM T-lymphocytes revealed that the Mannich bases were more cytotoxic than the corresponding unsaturated ketones. 1,4-bis(3-Dimethylaminomethyl-2-oxo-1-cyclohexylmethylene)benzene dihydrochloride (3a) had lower IC50 values than melphalan against the four cell lines and was 15 times more potent than this drug when examined against a panel of human tumours.
- Dimmock, Jonathan R,Jha, Amitabh,Kumar, Praveen,Zello, Gordon A,Quail, J.Wilson,Oloo, Eliud O,Oucharek, Jennifer J,Pasha, Mohammed K,Seitz, Dallas,Sharma, Rajendra K,Allen, Theresa M,Santos, Cheryl L,Manavathu, Elias K,De Clercq, Erik,Balzarini, Jan,Stables, James P
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- Novel synthesis of fully-substituted pyridine derivatives via self-condensation of cyclic ketones in aqueous ammonium chloride under hydrothermal conditions
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A new method for synthesizing fully-substituted pyridine derivatives was developed using the self-condensation of cyclic ketones in aqueous ammonium chloride under hydrothermal conditions.
- Kotsuki,Mehta,Yanagisawa
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p. 1323 - 1325
(2007/10/03)
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- Meerwein-Ponndorf-Verley-type reductive acetylation of carbonyl compounds to acetates by lanthanide complexes in the presence of isopropenyl acetate
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Meerwein-Ponndorf-Verley-type reductive acetylation of carbonyl compounds to acetates was successfully carried out in the presence of isopropenyl acetate under the influence of a catalytic amount of Ln(O(i)Pr)3 at room temperature. Various carbonyl compounds were converted into the corresponding acetates in fair to good yields. (C) 2000 Elsevier Science Ltd.
- Nakano, Yasushi,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 1565 - 1569
(2007/10/03)
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- Aldol-type condensation reactions of cyclic ketones by the W(CO)6/CCl4/UV system
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The cyclic ketones can be converted to their aldol-type condensation products by the W(CO)6/CCl4/UV system. The reaction was monitored by recording the IR and GC-MS spectra of the reaction mixture. The results support a mechanism that includes an intermediate carbene complex of tungsten.
- Bozkurt
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p. 252 - 255
(2007/10/03)
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- Cyclopentylidene-cyclopentanol in pereumery
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The invention relates to the use of 2-cyclopentylidene-cyclopentanol as fragrance and flavour material. The compound has an indolic odour and is therefore very useful for replacing indole in perfumes and flavourings. Unlike indole it is stable to light and in alkaline media and gives no discolouration.
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- Aldol Reaction and Robinson-Type Annelation Catalyzed by Lanthanoid Triisopropoxides
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Lanthanoid triisopropoxides are active catalysts for aldol reactions.Aldehydes give the corresponding β-hydroxyaldehydes at low temperatures in good yields, whereas ketones are less reactive, but form condensation products at high temperatures.Exceptionally, γ- or δ-diketones easily undergo condensation to give five- and six-membered unsaturated ketones in high yields.The lanthanoid propoxides, catalyzing the Michael addition of ketones to α,β-unsaturated ketones, which give δ-diketones, are also good catalysts for the Robinson-type annelation.In these reactions, the catalytic activity of the lanthanum propoxide is higher than those of the heavy lanthanoid propoxides, and is almost comparable to that of sodium isopropoxide.Since aluminum triisopropoxide shows poor activity, the lanthanoid propoxides are considerably basic for trivalent metal alkoxides.
- Okano, Tamon,Satou, Yoshikazu,Tamura, Motoshi,Kiji, Jitsuo
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p. 1879 - 1886
(2007/10/03)
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- Le (chlorodiisopropyl)silyl fluorenyllithium: un equivalent synthetique du diisopropyl(fluorenylidene)silene
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The metalation of chlorodiisopropylfluorenylsilane 1 with n-butyllithium leads to the α-silylthio compound 3.Compound 3 has a surprising stability and does not afford the diisopropyl(fluorenylidene)silene but behaves as its synthetic equivalent; i.e. it is a useful reagent for "Wittig-Peterson" reactions with various carbonyl compounds leading readily to diisopropylsilanone and fluorenylidene derivatives.
- Couret, C.,Escudie, J.,Delpon-Lacaze, G.,Satge, J.
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p. 233 - 242
(2007/10/02)
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- Carbocyclic ring expansion reactions via radical chain processes. Part II
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The further exploitation of the homolytic ring expansion of cyclohexanone derivatives is described. The application of this methodology to the preparation of exomethylene cycloalkanones, α-alkylated cyclodecanones, indanones, and decalinols is described.
- Baldwin,Adlington,Robertson
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p. 6795 - 6812
(2007/10/02)
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- Reactions of alkali metal anions. XV. Reaction of ketones with alkali metal anions
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The potassium anions were found to react with ketones to39 yield both alcoholates and enolates. On the basis of the ESR and K NMR measurements the mechanism of this reaction is proposed. According to the proposed mechanism in the first step a ketyl radical is formed which after disproportionation yields an enolate and an alcoholate but only in the case of ketones having hydrogen atom in α-position in respect to carbonyl group.
- Jedlinski,Misioiek,Giowkowski,Janeczek,Wolinska
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p. 3547 - 3558
(2007/10/02)
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- REACTION OF 9-DIAZO-4-AZAFLUORENE WITH UNSATURATED COMPOUNDS AND CYCLIC KETONES
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Spiro were obtained by the reaction of 9-diazo-4-azafluorene with various alkenes in the form of a mixture of geometrical isomers differentiated according to the position of the substituents in the cyclopropane ring and also according to position relative to the pyridine ring.In the reaction of 9-diazo-4-azafluorene with cyclopentanone, di(4-azafluorene-9-yl) oxide is formed, while from its reaction with cyclohexanone, 2'-oxo-spiro is obtained.
- Prostakov, N. S.,Varlamov, A. V.,Hussein, A.,Fomichev, A. A.,Ryabova, N. A.,Stashenko, E. E.
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p. 424 - 430
(2007/10/02)
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- Synthesis of α,β-Unsaturated Carbonyl Compounds by Titanium Tetraalkoxide-Induced Aldol Condensation under Neutral Conditions
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Aldehydes and ketones, when treated with titanium tetraalkoxides in a hydrocarbon solvent at 20-140 deg C, undergo aldol condensation to give α,β-unsaturated carbonyl compounds.To avoid Meerwein-Ponndorf-Verley type reduction of the carbonyl compounds, titanium tetra-tert-butoxide is used, if the reaction is carried out at higher temperatures.In all other cases titanium tetraisopropoxide can be successfully employed.The outlined procedure offers the possibility of performing aldol condensations under neutral conditions.
- Mahrwald, Rainer,Schick, Hans
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p. 592 - 595
(2007/10/02)
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- REACTION OF CYCLIC KETONES WITH KOH-DMSO
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Upon reaction of cycloalkanones with a KOH-DMSO system 2-methylenecycloalkanols are formed, the yield (10-37percent) of which decreases in the series: cyclohexanone > cycloheptanone > cyclooctanone > cyclododecanone
- Trofimov, B. A.,Petrova, O. V.,Vasil'tsov, A. M.,Mikhaleva, A. I.
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p. 1450 - 1453
(2007/10/02)
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- Reactivity of Dimethyl N-(Ethoxycarbonylmethyl)iminodithiocarbonate with Carbonyl Compounds in Basic Medium
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The reactivity of dimethyl N-(ethoxycarbonylmethyl)iminodithiocarbonate with aromatic aldehydes and reactive ketones has been studied.Ethyl 3-aryl-2-(methylcarbonylamino)acrylates (1) are obtained with aromatic aldehydes by ring-opening isomerization of the intermediate 5-aryl-4-ethoxycarbonyl-2-methylthio-4,5-dihydro-1,3-oxazoles (2).With ketones it has been shown that the cycloalkanones give rise to the corresponding alkylidene derivatives by a reaction path identical with that of aromatic aldehydes, whereas hexafluoropropanone and 1,1,1-trifluoropropanone display duality in acting as both acylating reagents and carbonyl compounds.
- Alvarez-Ibarra, Carlos,Lopez-Ranz, Maria M.,Lopez-Sanchez, Maria I.,Orellana, Guillermo,Ortiz, Paloma,Quiroga, Maria L.
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p. 1577 - 1584
(2007/10/02)
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