25564-22-1Relevant articles and documents
Concurrent Strong Acid and Base Catalysis. Synthesis of Cyclopentenones
Stowell, John C.,Hauck, Henry F.
, p. 2428 - 2429 (1981)
2-Alkyl-2-cyclopenten-1-ones were prepared in one operation from γ-keto aldehyde acetals by acid-catalyzed hydrolysis of the acetal and base-catalyzed aldol cyclization using mixed ion-exchange resins.
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Roumestant,M.L. et al.
, p. 755 - 757 (1976)
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Tsuji,J. et al.
, p. 39 - 40 (1979)
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Oshima,K. et al.
, p. 4446 - 4447 (1973)
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Catalytic intermolecular Pauson - Khand reactions in supercritical ethylene
Jeong, Nakcheol,Hwang, Sung Hee
, p. 636 - 638 (2000)
Ethylene is not only a substrate, but also a solvent: Catalytic intermolecular Pauson - Khand reactions of terminal alkynes were carried out in supercritical ethylene to provide 2-substituted cyclopentenones in moderate to high yields. Under these conditions, even a low pressure of CO (5 atm) is sufficient for the reaction to take place.
Characterization of initial reaction intermediates in heated model systems of glucose, glutathione, and aliphatic aldehydes
Wang, Tianze,Zhen, Dawei,Tan, Jia,Xie, Jianchun,Cheng, Jie,Zhao, Jian
, (2019/09/12)
To understand the effect of lipid degradation on Maillard formation of meaty flavors, initial reaction intermediates in model systems of glucose–glutathione with hexanal, (E)-2-heptenal, or (E,E)-2,4-decadienal were identified by HPLC–MS and by NMR. Besides Amadori compounds, hemiacetals and thiazolidines via addition of sulfhydryl to carbonyl or to the conjugated olefinic bond were found. Concentrations of all intermediates increased with reaction time while degradation of the intermediates with a glutathione moiety helped formation of thiazolidines with cysteinylglycine. The unsaturated aldehydes (E)-2-heptenal and (E,E)-2,4-decadienal exhibited high reactivity against glucose for glutathione, yielding higher levels of intermediate compounds than from glucose. Heating prepared intermediates reversibly released the original aldehydes, which caused various compounds formed by retro-aldol, oxidation, etc. to react with H2S and NH3. Among them, formation pathways including 3-nonen-2-one, 2-hexanoylfuran, and six dialkylthiophenes (e.g., 2-ethyl-5-(1-methylbutyl)thiophene) were proposed for the first time.
Method for preparing amyl cyclopentenone through organic solvent-free isomerization in methyl dihydrojasmonate synthesis
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Paragraph 0013-0015, (2020/01/03)
The invention discloses a method for preparing amyl cyclopentenone through organic solvent-free isomerization in methyl dihydrojasmonate synthesis. The method comprises: stirring and mixing p-toluenesulfonic acid and acetic anhydride in a reactor, heating to a temperature of 120 +/-2 DEG C while stirring, adding pentylidene cyclopentanone in a dropwise manner, carrying out thermal insulation stirring for 2-4 h at a temperature of 118-122 DEG C after the adding, cooling after the reaction is finished, regulating the pH value of the reaction solution to 7.5-9 by using a sodium carbonate solution, and carrying out standing layering to obtain an oil phase, wherein the oil phase is crude amyl cyclopentenone. According to the present invention, during the isomerization, no organic solvent is used so as to achieve clean and environmentally-friendly production.
Chemo-Enzymatic Oxidative Rearrangement of Tertiary Allylic Alcohols: Synthetic Application and Integration into a Cascade Process
Brenna, Elisabetta,Crotti, Michele,De Pieri, Matteo,Gatti, Francesco G.,Manenti, Gabriele,Monti, Daniela
supporting information, p. 3677 - 3686 (2018/06/04)
A chemo-enzymatic catalytic system, comprised of Bobbitt's salt and laccase from Trametes versicolor, allowed the [1,3]-oxidative rearrangement of endocyclic allylic tertiary alcohols into the corresponding enones under an Oxygen atmosphere in aqueous media. The yields were in most cases quantitative, especially for the cyclopent-2-en-1-ol or the cyclohex-2-en-1-ol substrates without an electron withdrawing group (EWG) on the side chain. Transpositions of macrocyclic alkenols or tertiary alcohols bearing an EWG on the side chain were instead carried out in acetonitrile by using an immobilized laccase preparation. Dehydro-Jasmone, dehydro-Hedione, dehydro-Muscone and other fragrance precursors were directly prepared with this procedure, while a synthetic route was developed to easily transform a cyclopentenone derivative into trans-Magnolione and dehydro-Magnolione. The rearrangement of exocyclic allylic alcohols was tested as well, and a dynamic kinetic resolution was observed: α,β-unsaturated ketones with (E)-configuration and a high diastereomeric excess were synthesized. Finally, the 2,2,6,6-tetramethyl-1-piperidinium tetrafluoroborate (TEMPO+BF4?)/laccase catalysed oxidative rearrangement was combined with the ene-reductase/alcohol dehydrogenase cascade process in a one-pot three-step synthesis of cis or trans 3-methylcyclohexan-1-ol, in both cases with a high optical purity. (Figure presented.).
