Search results for "Diketone"
showing 10 items of 34 documents
Untersuchungen zur Konformation von 2‐Diazo‐1,3‐diketonen
1988
Mit Hilfe von 1H- und 13C-NMR-Messungen in Losung (und im Festkorper) werden die Konformationen von 2-Diazo-1,3-diketonen (2a–f) mit sperrigen Resten untersucht. Investigation on the Conformation of 2-Diazo-1,3-diketones Conformational analyses of 2-diazo-1,3-diketones (2a–f) with bulky substituents are performed by applying 1H- and 13C-NMR measurements in solution (and in solid state).
Antidiabetische wirkstoffe, IV [1] trifluormethylsubstituierte 2-(4-toluidino)pyrimidine
1985
Zusammenfassung Durch Umsetzung von 4-Tolylguanidin mit den entsprechenden fluorierten β-Diketonen in Gegenwart von Natriumcarbonat im Schmelzfluβ sind die folgenden 4-Trifluormethyl-2-(4-toluidino) pyrimidine zuganglich gemacht worden: die 6-Methyl-, 6-Ethyl-, 6-Isopropyl-, 6-tert. Butyl- und 6-Isopentyl-Abkommlinge. Zur Charakterisierung der dargestellten Verbindungen sind IR-, 1H-NMR- und MS-Daten herangezogen worden. In dem neuen Strukturtyp sind besonders antidiabetische, antimykotische, trichomonazide und herbizide Wirksamkeit ausgepragt.
A short synthesis of dimethyl tricyclo[3.3.0.0 3,7 ]octane‐1,5‐dicarboxylate and its 3,7‐dimethyl derivative. A new route to the tricyclo[3.3.0.0 3,7…
1988
Five-step syntheses of dimethyl tricyclo[3.3.0.03,7]octane-1,5-dicarboxylate (13) and its 3,7-dimethyl derivative 14 from the readily available cis-bicyclo[3.3.0]octane-3,7-diones 1 and 2, respectively, are described. The key-step implies the iodine oxidation of the bis-enolate derived from the corresponding dimethyl cis-bicyclo-[3.3.0]octane-3,7-dicarboxylates 11 and 12, thus being developed a new synthetic entry into the tricyclo[3.3.0.03,7]octane skeleton. Also, some attempts to synthesize diester 13 by using known methodology for the synthesis of compounds containing this tricyclic skeleton are described. Eine kurze Synthese von Tricyclo [3.3.0.03,7]octan-1,5-dicarbonsaure-dimethylester…
Kinetische Untersuchungen zur Bildung der E ‐ und Z ‐Enole bei der Thermolyse von 2‐Diazo‐1,3‐dimesityl‐1,3‐propandion in Nucleophilen
1988
Bei der Thermolyse der Diazoverbindung 1 in Ethanol bzw. Piperidin oder Morpholin entstehen die Enole 3a–c von β-Ketocarbonsaurederivaten. Z- und E-Konfigurationen stehen miteinander im Gleichgewicht. Die Bestimmung der Geschwindigkeits-konstanten zeigt, das sich zunachst bevorzugt die Z-Formen bilden; im Gleichgewicht dominieren jedoch schlieslich in den Thermolysemedien die E-Isomeren. In aprotischen, apolaren oder masig polaren Medien uberwiegen dagegen die Z-Isomeren mit einer intramolekularen Wasserstoffbrucke. Investigation on the Kinetics of the Formation of E- and Z-Enols in the Thermolysis of 2-Diazo-1,3-propanedione in Nucleophiles Thermolysis of the diazo compound 1 in ethanol an…
Improved Regioselectivity in Pyrazole Formation through the Use of Fluorinated Alcohols as Solvents: Synthesis and Biological Activity of Fluorinated…
2008
The preparation of N-methylpyrazoles is usually accomplished through reaction of a suitable 1,3-diketone with methylhydrazine in ethanol as the solvent. This strategy, however, leads to the formation of regioisomeric mixtures of N-methylpyrazoles, which sometimes are difficult to separate. We have determined that the use of fluorinated alcohols such as 2,2,2-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as solvents dramatically increases the regioselectivity in the pyrazole formation, and we have used this modification in a straightforward synthesis of fluorinated analogs of Tebufenpyrad with acaricide activity. Fil: Fustero, Santos. Universidad de Valencia; España Fil…
ELABORATION OF CURCUMIN INTO DIKETONE MODIFIED ANALOGUES DEVOID OF NUCLEOPHILIC ADDITION CAPABILITY; IMPLICATIONS FOR THEIR ANTITUMOR AND CHEMOSENSIT…
2009
Curcumin (CUR), a polyphenolic compound extracted from Curcuma longa L.,can beconsidered as a good lead compound for the design of new drugs for the treatment of cancer and other therapeutic purposes. CUR is endowed with a diketone function, which appears to be important for its antitumor activity: also depending on the dose, the compound may show complex either pro-oxidant or anti-oxidant effects, which both may, at least in part, be linked to this structural moiety. In the lower concentration, "chemopreventive", range, CUR behaves mainly as an antioxidant; at higher concentrations, the a, b-unsaturated 1,3-diketone, as a Michael acceptor, can form adducts with the –SH groups and generate …
CCDC 207302: Experimental Crystal Structure Determination
2004
Related Article: H.Werner, N.Mahr, J.Wolf, A.Fries, M.Laubender, E.Bleuel, R.Garde, P.Lahuerta|2003|Organometallics|22|3566|doi:10.1021/om0302037
Synthesis of new fluorinated Tebufenpyrad analogs with acaricidal activity through regioselective pyrazole formation.
2008
In previous studies, our group has shown that the use of fluorinated alcohols such as trifluoroethanol (TFE) and hexafluoroisopropanol (HFIP) as solvents dramatically increases the regioselectivity in the pyrazole formation from 1,3-diketone with methylhydrazine. We have now applied this synthetic method to the preparation of new fluorinated pyrazoles, which have then been used as synthetic intermediates in the preparation of fluorinated analogs of Tebufenpyrad, a commercial acaricide. These compounds display a strong acaricidal activity that is either comparable to or better than that of the commercial compound.
Study of the interaction of [Cu(bipy)]2+ with oxalate and squarate in aqueous solution
1988
A study of the formation of complexes between [Cu(bipy)]2+ and ox2− and sq2− in aqueous solution, (bipy being 2,2′-bipyridine and ox2− and sq2− the dianions of ethanedioic acid and 3,4-dihydroxy-3-cyclobutene-1,2-dione, respectively), has been carried out with the aim of comparing the coordinating properties of these related ligands. The constants of the equilibria (i) and (ii) $$[Cu(bipy)]^{2 + } + ox^{2 - } \rightleftharpoons [Cu(bipy)ox]$$ (i) $$[Cu(bipy)]^{2 + } + sq^{2 - } \rightleftharpoons [Cu(bipy)sq]$$ (ii) have been determined by potentiometry and spectrophotometry at 25.0°C and 0.1 M NaNO3:logβ=5.78(2) and 2.16(2) for the oxalato- and squarato-complex, respectively. Such differen…
A novel photochemical 1,4-acyl migration in enol esters. The photolysis of enol acetates of 3-phenylpropiophenones
1987
Abstract Photolysis of the enol acetates 1a,b gives the 1,4-diketones 4a,b by a mechanism involving a primary homolytic carbonyl—oxygen bond cleavage, followed by 1,2-hydrogen shift and in cage recombination.