2758-18-1Relevant articles and documents
Vapor-phase intramolecular aldol condensation of 2,5-hexanedione to 3-methylcyclopent-2-enone over ZrO2-supported Li2O catalyst
Sun, Daolai,Chiba, Shigenori,Yamada, Yasuhiro,Sato, Satoshi
, p. 105 - 108 (2017)
Vapor-phase intramolecular aldol condensation of 2,5-hexanedione to produce 3-methylcyclopent-2-enone was performed over several ZrO2-supported alkali and alkali earth metal oxides. Among the tested catalysts, ZrO2-supported Li2O showed a stable catalytic activity. A high 2,5-hexanedione conversion of 99% with a 3-methylcyclopent-2-enone selectivity of 96% was achieved over a 20?mol% Li2O-loaded ZrO2catalyst at 250?°C.
Total synthesis of jiadifenolide
Paterson, Ian,Xuan, Mengyang,Dalby, Stephen M.
, p. 7286 - 7289 (2014)
As a potent neurotrophic agent, the sesquiterpenoid jiadifenolide represents a valuable small-molecule lead for the potential therapeutic treatment of neurodegenerative diseases. A stereocontrolled total synthesis of this densely functionalized natural product is reported, central to which is an adventurous samarium-mediated cyclization reaction to establish the tricyclic core and the adjacent C5 and C6 quaternary stereocenters.
Synthesis of Bio-Based Methylcyclopentadiene from 2,5-Hexanedione: A Sustainable Route to High Energy Density Jet Fuels
Woodroffe, Josanne-Dee,Harvey, Benjamin G.
, p. 339 - 343 (2021)
The sustainable, bio-based, platform chemical, 2,5-hexanedione [HD (1)], was efficiently converted to methylcyclopentadiene [MCPD (4)] through a three-step process consisting of intramolecular aldol condensation, catalytic chemoselective hydrogenation, and dehydration. Base-catalyzed aldol condensation of 1 resulted in the formation of 3-methyl-2-cyclopenten-1-one [MCO (2)], which was then converted to 3-methyl-2-cyclopenten-1-ol [MCP (3)] by chemoselective reduction with a ternary Ru catalyst system [RuCl2(PPh3)3/NH2(CH2)2NH2/KOH]. The hydrogenation proceeded with 96 % chemoselectivity. 3 was then dehydrated over AlPO4/MgSO4 at 70 °C under reduced pressure to yield 4, which can undergo an ambient temperature [4+2]-Diels-Alder cyclization to generate dimethyldicyclopentadiene (DMDCPD), a commodity chemical useful for the preparation of high-performance fuels and polymers. Through this approach, advanced jet fuels and materials can be conveniently produced from sustainable cellulosic feedstocks.
Tantalum vs Niobium MCF nanocatalysts in the green synthesis of chromene derivatives
Smuszkiewicz, Agata,López-Sanz, Jesús,Sobczak, Izabela,Martín-Aranda, Rosa M.,Ziolek, Maria,Pérez-Mayoral, Elena
, p. 47 - 52 (2019)
TaMCF silicas modified with alkaline metals can be considered a novel family of highly efficient bifunctional catalysts involved in the synthesis of chromene derivatives, from salicylaldehyde 2 and acetonitrile compounds, under mild conditions, showing enhanced catalytic performance than their NbMCF analogues. The observed reactivity was mainly attributed to the higher basicity of the Me/TaMCF but also the texture of the samples. The Me/TaMCF silicas showed higher Br?nsted basicity than the Nb ones as indicated by the stronger interaction between alkali metals and Ta in the UV–vis and the test reaction experiments. On the other hand, the basicity of Me/TaMCF together the reactivity degree and steric hindrance of the starting acetonitriles are key factors influencing the reaction selectivity. In conclusion, the basicity of the samples plays an important role initiating the reaction by activation of nucleophile but also a compromise between alkaline cation size and basicity is required.
Calcium and nitrogen species loaded into SBA-15-a promising catalyst tested in Knoevenagel condensation
Kryszak, Dorota,Stawicka, Katarzyna,Trejda, Maciej
, p. 9781 - 9794 (2020)
Mesoporous silica of the SBA-15 type was used as a support for basic active centers generated by the incorporation of calcium species and (3-aminopropylo)trimethoxysilane (APTMS) or imidazole. The samples were characterized by low temperature N2 adsorption/desorption, XRD, XPS, FTIR spectroscopy, CO2-TPD, and elemental and thermal analyses. Calcium containing samples were analysed in 2,5-hexanedione dehydration and cyclization, while the activities of all the samples were examined in Knoevenagel condensation between benzaldehyde and malononitrile. It was demonstrated that the calcium species interacted with a silica support increasing the stabilization of organosilanes on the SBA-15 surface. A very high activity of the catalysts in Knoevenagel condensation indicated a synergistic interaction between calcium and the organic modifiers.
Transformation of γ-ketoaldehyde acetals into 3-substituted-2-cyclopentenones via cyanophosphates under mild conditions
Yoneyama, Hiroki,Takatsuji, Kumi,Ito, Aiko,Usami, Yoshihide,Harusawa, Shinya
, (2021/02/06)
The reaction of cyanophosphates, which are readily derived from γ-ketoaldehyde acetals, with TMSN3 (3 eq)/Bu2SnO (0.3 eq) in refluxing toluene directly furnished 3-substituted-2-cyclopentenones in modest to good yield under mild conditions. The present method was further applied toward the synthesis of dechlorotrichodenone C isolated from Trichoderma asperellum.
Producing methylcyclopentadiene dimer and trimer based high-performance jet fuels using 5-methyl furfural
Dai, Yiying,Liu, Qing,Liu, Yakun,Liu, Yanan,Ma, Chi,Nie, Genkuo,Pan, Lun,Shi, Chengxiang,Zhang, Xiangwen,Zou, Ji-Jun
, p. 7765 - 7768 (2020/12/01)
Methylcyclopentadiene dimer and trimer based fuels are synthesized from 5-methyl furfural for the first time with yields as high as 74.4%. They exhibit both high density and high thermal stability that are better than those of widely used fossil based jet fuels such as JP-10 and JP-7, and represent types of high-performance fuels. This work also provides a potential and scale-up feasible route for synthesizing high-performance jet fuels from biomass.
Tris(2-aminoethyl)amine/metal oxides hybrid materials—preparation, characterization and catalytic application
Stawicka, Katarzyna,Ziolek, Maria
, (2020/10/29)
Three different metal oxides (basic MgO, basic-acidic Al2O3 and acidic-basic Nb2O5) characterized by comparable surface areas (MgO—130 m2/g; Al2O3—172 m2/g and Nb2O5—123 m2/g) and pore systems (domination of mesopores with narrow pore size distribution) were modified with tris(2-aminoethyl)amine (TAEA) via two methods: (i) direct anchoring of amine on metal oxide and (ii) anchoring of amine on metal oxide functionalized with (3-chloropropyl)trimethoxysilane. The obtained hybrid materials were characterized in terms of effectiveness of modifier anchoring (elemental analysis), their structural/textural properties (nitrogen adsorption/desorption, XRD), acidity/basicity of support (2-propanol dehydration and dehydrogenation, dehydration and cyclization of 2,5-hexanedione), states of modifier deposited on supports (XPS, FTIR, UV–VIS) and the strength of interaction between the modifier and the support (TG/DTG). It was evidenced that acidic-basic properties of metal oxides as well as the procedure of modification with TAEA determined the ways of amine anchoring and the strength of its interaction with the support. The obtained hybrid materials were tested in Knoevenagel condensation between furfural and malononitrile. The catalysts based on MgO showed superior activity in this reaction. It was correlated with the way of TAEA anchoring on basic MgO and the strength of modifier anchoring on the support. To the best of our knowledge tris(2-aminoethyl)amine has not been used as a modifier of solid supports for enhancement of the catalyst activity in Knoevenagel condensation.
Preparation method of 3-methyl-2-cyclopentene-1-one
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Paragraph 0023-0025; 0028-0038; 0045-0054; 0056-0063, (2020/12/15)
The invention provides a preparation method of 3-methyl-2-cyclopentene-1-one. A device comprises a coiled tube type reactor and two plunger pumps, the output ends of the plunger pumps are connected with the coiled tube type reactor, and the coiled tube type reactor is placed in an oil bath pan at 120-130 DEG C. The preparation method comprises the following steps: S1, preparing a 2, 5-hexanedioneaqueous solution and a 20% sodium hydroxide solution; S2, respectively immersing the plunger pumps into the 2, 5-hexanedione aqueous solution and the 20% sodium hydroxide solution, and setting the flow rate to be 10-18 mL/min; and S3, placing a 1 L four-necked bottle at the outlet of the reactor, cooling with heat-conducting oil at the temperature of 0-5 DEG C in an external bath, stopping the reaction and sampling after receiving the reaction liquid for 30 minutes, extracting with acetic acid, and carrying out GC analysis. According to the invention, a continuous reaction technology is adopted, and the reaction selectivity is regulated by adjusting the molar ratio, the feeding rate and the residence time of materials; and the reaction solution is collected and cooled after the reaction isfinished, thereby avoiding the quick decomposition of the product in the hot alkali liquor. Water is used as a solvent, and reaction is carried out at a low temperature, so environmental pollution isreduced, and energy consumption is reduced. And the yield of the prepared 3-methyl-2-cyclopentene-1-one reaches 70-75%.
Production of oxygen-containing alicyclic compounds (by machine translation)
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Paragraph 0035; 0037; 0038, (2020/04/24)
[Problem] to provide, in a one-step reaction synthesizes an alicyclic compound containing oxygen, high yield production of oxygen-containing compound is a cycloaliphatic. [Solution] one or more hydroxy or carbonyl group 2, or a hydroxyl group having the carbon number of 5 or more aliphatic carbonyl group 2 in accordance with one or more oxygen-containing compound, a basic catalyst is brought into contact with an oxygen-containing alicyclic compound by cyclodehydration reaction, oxygen-containing alicyclic compound. [Drawing] no (by machine translation)
