625-33-2Relevant academic research and scientific papers
Cassis and Green Tea: Spontaneous Release of Natural Aroma Compounds from β-Alkylthioalkanones
B?ttig, Sarah,Bochet, Christian G.,Egger, Timothy,Flachsmann, Felix,Gey, Olga
, (2021/10/19)
In depth headspace analysis of the slow degradation of β-alkylthioalkanones in ambient air led to the discovery of a novel δ-cleavage pathway, by which β-mercaptoketones are released. Since β-mercaptoketones are potent natural aroma compounds occurring in many fruits, herbs and flowers, the discovery of an enzyme-independent molecular precursor for this class of high-impact molecules is of practical importance. Moreover, the formation of β-diketones and aldehydes by concomitant oxidation at the α-sulfur-position enhances the versatility of this class of aroma precursors. A mechanistic model is proposed which suggests that the oxidative degradation occurs through a novel Pummerer-type rearrangement of initially formed persulfoxides.
Direct Catalytic Conversion of Ethanol to C5+ Ketones: Role of Pd–Zn Alloy on Catalytic Activity and Stability
Bathena, Tanmayi,Goulas, Konstantinos A.,Gray, Michel,Guo, Mond F.,Kovarik, Libor,Martinez, Abraham,Ramasamy, Karthikeyan K.,Subramaniam, Senthil,Zhang, Xiao
, p. 14550 - 14557 (2020/07/08)
Ethanol can be used as a platform molecule for synthesizing valuable chemicals and fuel precursors. Direct synthesis of C5+ ketones, building blocks for lubricants and hydrocarbon fuels, from ethanol was achieved over a stable Pd-promoted ZnO-ZrO2 catalyst. The sequence of reaction steps involved in the C5+ ketone formation from ethanol was determined. The key reaction steps were found to be the in situ generation of the acetone intermediate and the cross-aldol condensation between the reaction intermediates acetaldehyde and acetone. The formation of a Pd–Zn alloy in situ was identified to be the critical factor in maintaining high yield to the C5+ ketones and the stability of the catalyst. A yield of >70 percent to C5+ ketones was achieved over a 0.1 percent Pd-ZnO-ZrO2 mixed oxide catalyst, and the catalyst was demonstrated to be stable beyond 2000 hours on stream without any catalyst deactivation.
Construction of Multiple-Substituted Chiral Cyclohexanes through Hydrogenative Desymmetrization of 2,2,5-Trisubstituted 1,3-Cyclohexanediones
Yu, Chang-Bin,Song, Bo,Chen, Mu-Wang,Shen, Hong-Qiang,Zhou, Yong-Gui
supporting information, p. 9401 - 9404 (2019/11/28)
The construction of chiral multiple-substituted cyclohexanes motifs is a challenging topic in organic synthesis. By the combination of desymmetrization and remote stereocontrol, a ruthenium-catalyzed transfer hydrogenative desymmetrization of 2,2,5-trisubstituted 1,3-cyclohexanediones has been successfully developed for the construction of chiral multiple-substituted cyclohexanes with high enantioselectivity and diastereoselectivity. When an ester group was introduced to the two-position, a hydrogenative desymmetrization/transesterification cascade occurred, affording the bicyclic lactones bearing three stereocenters, including two discrete stereocenters and one quaternary stereogenic center, with high enantioselectivity. The products are the multiple-substituted chiral cyclohexanes bearing the hydroxyl and carbonyl functional groups, which provide a new opportunity for further precise elaboration.
4-furfurylthiopentanone-2 preparation method
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Paragraph 0078; 0082-0083, (2019/11/04)
The invention belongs to the technical field of fine chemistry, and provides a 4-furfurylthiopentanone-2 preparation method, which specifically comprises: adding a raw material chloroacetone to a toluene solution of triphenylphosphine or to triethyl phosphite, and carrying out a heating reflux reaction to obtain a phosphorus salt; dissolving the obtained phosphorus salt in an organic solvent, adding a strong alkali, stirring for 2-3 h, and obtaining phosphorus ylide after completing a reaction; adding the phosphorus ylide to an acetaldehyde aqueous solution or paraldehyde, and stirring until the reaction is completed to obtain 3-pentene-2-ketone; adding piperidine to the 3-pentene-2-ketone, adding a dichloromethane solution of furfuryl mercaptan in a dropwise manner, and controlling the temperature of the system during the adding at 35-40 DEG C; and after the adding, stirring until the reaction is completed so as to obtain the product 4-furfurylthiopentanone-2. According to the present invention, with the method, the problems of high risk, high cost and being unsuitable for industrial production of the 4-furfurylthiopentanone-2 synthesis route in the prior art are solved.
Synthesis of 1-hydrocarbon substituted cyclopropyl silyl ketones
Honda, Mitsunori,Sasaki, Sho,Nishimoto, Tsuyoshi,Koshiro, Hiromoto,Kunimoto, Ko-Ki,Segi, Masahito
, p. 3777 - 3781 (2018/09/21)
The synthesis of cyclopropyl silyl ketones possessing a hydrocarbon group at 1-position of three-membered ring was investigated. The reaction of sulfoxonium ylide with α,β-unsaturated acylsilanes derived from α,β-unsaturated aldehydes did not afford the desired acylsilane derivatives. Instead, the corresponding silyl enol ethers were yielded exclusively. On the other hand, the Corey-Chaykovsky cyclopropanation of α-substituted α,β-unsaturated aldehydes proceeded well to give 1-substituted cyclopropyl aldehydes. The silyl substitution of formyl proton in the obtained aldehydes via umpolung of carbonyl group afforded the target acylsilanes.
Synthetic approaches to phomactins: Novel oxidation of homoallylic alcohols using tetra-n-propylammonium perruthenate
Blackburn, Timothy J.,Thomas, Eric J.
, p. 5399 - 5407 (2018/06/20)
Previous studies of a synthesis of phomactin A had resulted in the synthesis of a 15-methylenebicyclo[9.3.1]pentadecadiene. The next step in the synthesis was to be the epoxidation of this methylenecyclohexane that was hoped would lead to a 1-(hydroxymethyl)cyclohexene by rearrangement of the exocyclic epoxide, but the epoxidation was difficult to carry out regioselectively on advanced intermediates. However, oxidation of a 15-methylenebicyclo[9.3.1]pentadeca-3,7-dien-14-ol using tetra-n-propylammonium perruthenate and N-methylmorpholine-N-oxide led to conversion of this homoallylic alcohol into the corresponding 14-oxobicyclo[9.3.1]pentadeca-1(15),3,7-triene-15-carboxaldehyde in one step. Reduction of this using DIBAL-H gave a promising intermediate for a synthesis of a phomactin. The scope of this oxidation of homoallylic alcohols was briefly investigated.
Biocatalytic Racemization Employing TeSADH: Substrate Scope and Organic Solvent Compatibility for Dynamic Kinetic Resolution
Pop?oński, Jaros?aw,Reiter, Tamara,Kroutil, Wolfgang
, p. 763 - 768 (2018/02/27)
Racemization in combination with a kinetic resolution is the base for a dynamic kinetic resolution (DKR). Biocatalytic racemization was successfully performed for a broad scope of sec-alcohols by employing a single alcohol dehydrogenase (ADH) variant from Thermoanaerobacter pseudoethanolicus (formerly T. ethanolicus; TeSADH W110A I86A C295A). The catalyst employed as a lyophilized whole cell preparation or cell free extract, which tolerated various non-water miscible organic solvents under micro-aqueous or two-phase conditions, whereby cyclohexane and n-hexane suited best. Various concepts for combining the enzymatic racemization with an enzymatic kinetic resolution to achieve overall a bis-enzymatic DKR were evaluated. A proof of concept showed a successful DKR with racemization in aqueous phase combined with acylation in the organic phase.
Enzyme-catalyzed domino reaction: Efficient construction of spirocyclic oxindole skeleton using porcine pepsin
He, Yan-Hong,He, Tao,Guo, Jun-Tao,Li, Rui,Xiang, Yang,Yang, Da-Cheng,Guan, Zhi
, p. 2239 - 2248 (2016/04/26)
Pepsin from porcine gastric mucosa was used as a sustainable and environmentally friendly biocatalyst in the domino Knoevenagel/Michael/Michael reaction for the synthesis of spirooxindole derivatives in methanol. A wide range of isatins and α,β-unsaturated ketones reacting with malononitrile provided the corresponding products in yields of up to 99% with diastereoselectivities of up to >99:1 dr. This pepsin-catalyzed domino reaction provided a novel case of enzyme catalytic promiscuity.
Characterization of the monolignol oxidoreductase AtBBE-like protein 15 L182V for biocatalytic applications
Pils, Sabine,Schnabl, Kordula,Wallner, Silvia,Daniel, Bastian,Macheroux, Peter,Kljajic, Marko,Kupresanin, Nina,Breinbauer, Rolf,Fuchs, Michael,Rocha, Raquel,Schrittwieser, Joerg H.,Kroutil, Wolfgang
, p. S6 - S14 (2018/04/05)
Monolignol oxidoreductases from the berberine bridge enzyme-like (BBE-like) protein family (pfam 08031) catalyze the oxidation of monolignols to the corresponding aldehydes. In this report, we explore the potential of a monolignol oxidoreductase from Arabidopsis thaliana (AtBBE-like protein 15) as biocatalyst for oxidative reactions. For this study we employed a variant with enhanced reactivity towards oxygen, which was obtained by a single amino acid exchange (L182V). The pH and temperature optima of the purified AtBBE-like protein 15 L182V were determined as well as the tolerance toward organic co-solvents; furthermore the substrate scope was characterized. The enzyme has a temperature optimum of 50 °C and retains more than 50% activity between pH 5 and pH 10 within 5 min. The enzyme shows increased activity in the presence of various co-solvents (10–50% v/v), including acetonitrile, 2-propanol, 1,4-dioxane, and dimethyl sulfoxide. Primary benzylic and primary or secondary allylic alcohols were accepted as substrates. The enantioselectivity E in the oxidation of secondary alcohols was good to excellent (E>34 to?>200).
A multicomponent pathway-inspired regioselective synthesis of 2,3,4-trisubstituted 1H-pyrroles via [3+2] cycloaddition reaction
Kalmode, Hanuman P.,Vadagaonkar, Kamlesh S.,Murugan, Kaliyappan,Chaskar, Atul C.
, p. 4631 - 4639 (2015/06/16)
A copper catalyzed regioselective synthesis of 2,3,4-trisubstituted 1H-pyrroles using a novel three-component coupled domino reaction of aldehydes, ketones and alkyl isocyanoacetates is reported. This transformation proceeds through the formation of a chalcone followed by a [3+2] cycloaddition reaction to obtain α-cuprioisocyanide, a cyclic organocopper intermediate, which on copper-hydrogen exchange followed by oxidation exclusively offers 2,3,4-trisubstituted 1H-pyrrole.
