Search results for "Cyclohexanone"
showing 10 items of 31 documents
Composition-dependent Flory-Huggins parameters: molecular weight influences at high concentrations
1995
Flory-Huggins interaction parameters X were determined by means of equilibrium vapor pressures (measured via a combination of a head-space sampler with a gas chromatograph) and light scattering as a function of composition and temperature for the systems cyclohexanone/polystyrene [CHO/PS] and cyclohexanone/poly(butyl methacrylate) [CHO/PBMA]. The investigation of molecular weight influences on X with the system CHO/PBMA demonstrates that they persist almost up to the pure polymer. In order to rationalize this result, it is postulated (in accord with experimental findings and theoretical predictions) that the dimensions of polymer chains may vary upon the addition of solvent even in highly c…
Zur C-17-Oxidation von Clavinalkaloiden mit primärer alkoholischer Hydroxylgruppe
1975
Die Oppenauer-Oxidation von 1 mit Cyclohexanon fuhrt zu dem Aldolkondensationsprodukt 4 und der Carbonsaure 3. Analog konnte Lysergsaure (8) in geringer Menge aus 6 gewonnen und im Reaktionsgemisch von 7 nachgewiesen werden. Damit wurden erstmals Clavinalkaloide mit primarer alkoholischer Hydroxylgruppe chemisch zu den entsprechenden Carbonsauren oxidiert. C-17-Oxidation of Clavine Alkaloids with a Primary Alcoholic Hydroxyl Group. 1 is converted by Oppenauer oxidation with cyclohexanone to the aldol condensation product 4 and to the carboxylic acid 3. Lysergic acid (8) was obtained in a small yield by the analogous reaction of 6 and was found in the reaction mixture of 7. Thus clavine alka…
1985
Viscosity measurements were carried out as a function of pressure and temperature with solutions of 8 wt.-% PVC (Mw ≈ 75 000) in ten thermodynamically good solvents by means of a Searle-type viscometer. A rollingxyhball viscometer was used for the investigation of the pure solvents. In all cases the viscosity increases in a more or less exponential manner when the pressure is raised. The viscosity ratio f1000 = η1000 bar/η1bar can be varied by the choice of the solvent from ca. 2 (tetrahydrofuran) to 3,0 (cyclohexanone) at 40°C. For a constant temperature of 40°C, the volumes of activation for the viscous flow of the solutions, V≠, or f1000 exceed that of the pure solvent, by typically 25%.…
ChemInform Abstract: A Liquid-Liquid Biphasic Homogeneous Organocatalytic Aldol Protocol Based on the Use of a Silica Gel Bound Multilayered Ionic Li…
2012
Key feature of the title protocol is the use of a cis-ion-tagged proline dissolved in a liquid film on a multilayered ionic liquid covalently bound to silica. The resulting catalytically active material is soaked in cyclohexanone and water to form a semi-transparent gel which then reacts with the aldehyde.
Synthesis and characterization of a new spirooxindole grafted pyrrolidino/piperidine moiety
2021
In this text, we synthesized and characterized a new spirooxindole grafted pyrrolidino/piperidine moieties. The new hit obtained via one-pot reaction of the chalcone based cyclohexanone with the isatin and (R)-piperidine-2-carboxylic acid in MeOH under reflux for 48 h. The compound exclusively obtained in regio-selective and diastereo-selective manner. The chemical feature of the target compound is confirmed by 1H NMR and 13C NMR spectroscopy. In addition, we reported for the first time the X-ray single crystal structure of isatin. Its molecular packing depends mainly on strong O…H hydrogen bonds and π-π stacking interactions as well as weak H…H and H…C contacts. Using DFT calculations, is…
ChemInform Abstract: New Simple Hydrophobic Proline Derivatives as Highly Active and Stereoselective Catalysts for the Direct Asymmetric Aldol Reacti…
2009
New 4-substituted acyloxyproline derivatives with different hydrophobic properties of the acyl group were easily synthesized and used as catalysts in the direct asymmetric aldol reaction between cyclic ketones (cyclohexanone and cyclopentanone) and several substituted benzaldehydes. Reactions were carried out using water, this being the best reaction medium examined. Screening of these catalysts showed that compounds bearing the most hydrophobic acyl chains [4-phenylbutanoate and 4-(pyren-1-yl)butanoate] provided better results. The latter catalysts were successfully used in only 2 mol% at room temperature without additives to give aldol products in excellent stereoselectivities. These resu…
Crystal structure of 5′′-benzylidene-1′-methyl-4′-phenyltrispiro[acenaphthylene-1,2′-pyrrolidine-3′,1′′-cyclohexane-3′′,2′′′-[1,3]dioxane]-2,6′′-dione
2016
In the title trispiro compound, both the methyl-substituted pyrrolidine and dioxalane rings adopt a twist conformation. The cyclopentanone ring of the acenapthylen-1-one system adopts flattened envelope conformation, and the cyclohexanone attached to the dioxalane ring adopts boat conformation. In the crystal, centrosymmetrically related molecules are linked into dimers forming rings of (10) graph-set motif, which are further connected into chains parallel to the b axis by C—H⋯O contacts forming rings of (8) graph-set motif.
Advances towards highly active and stereoselective simple and cheap proline-based organocatalysts
2010
Ten 4-acyloxy-L-prolines were screened as catalysts at loadings of 2–0.1 mol-% for the direct asymmetric aldol reaction in water by using variable amounts of water. Among them, a new catalyst, the L-proline carrying a trans-4-(2,2-diphenylacetoxy) group, and a catalyst previously synthesized by us, the L-proline carrying a trans-4-(4-phenylbutanoyloxy) group, were found to be excellent catalysts for the aldol reaction between cyclohexanone or cyclopentanone and substituted benzaldehydes when employed in only 1 and 0.5 mol-%,respectively, at room temperature without additives. For such catalysts, high turnover numbers were obtained, which are among the highest values obtained for enamine org…
N-Cinnamoyltetraketide Derivatives from the Leaves of Toussaintia orientalis
2015
Seven N-cinnamoyltetraketides (1−7), including the new Ztoussaintine E (2), toussaintine F (6), and toussaintine G (7), were isolated from the methanol extract of the leaves of Toussaintia orientalis using column chromatography and HPLC. The configurations of E-toussaintine E (1) and toussaintines A (3) and D (5) are revised based on single-crystal X-ray diffraction data from racemic crystals. Both the crude methanol extract and the isolated constituents exhibit antimycobacterial activities (MIC 83.3−107.7 μM) against the H37Rv strain of Mycobacterium tuberculosis. Compounds 1, 3, 4, and 5 are cytotoxic (ED50 15.3−105.7 μM) against the MDA-MB-231 triple negative aggressive breast cancer cel…
New simple hydrophobic proline derivatives as highly active and stereoselective catalysts for the direct asymmetric aldol reaction in aqueous medium
2008
New 4-substituted acyloxyproline derivatives with different hydrophobic properties of the acyl group were easily synthesized and used as catalysts in the direct asymmetric aldol reaction between cyclic ketones (cyclohexanone and cyclopentanone) and several substituted benzaldehydes. Reactions were carried out using water, this being the best reaction medium examined. Screening of these catalysts showed that compounds bearing the most hydrophobic acyl chains [4-phenylbutanoate and 4-(pyren-1-yl)butanoate] provided better results. The latter catalysts were successfully used in only 2 mol% at room temperature without additives to give aldol products in excellent stereoselectivities. These resu…