Umwandlung der Ketone in ?-Diketone

The boron-mediated ketone-ketone aldol reaction

The first examples of the directed, boron-mediated aldol reaction between different ketones are presented. Transformation of a variety of ketones to their corresponding boron enolates with Chx2BCl/Et3N, followed by reaction with acceptor ketones in diethyl ether, and oxidation of the resultant boron aldolate (H2O2, MeOH/pH 7 buffer), provided the aldol addition products. The reaction was most f...

Electron - impact spectroscopy of various diketone compoundsa >

The spectra ofthe diketone compounds biacetyl, acetylacetone, acetonylacetone, 1,2cyclohexanedione, and 1,4-cyclohexanedione have been investigated by the technique oflowenergy variable-angle electron energy-loss spectroscopy. With this method low-lying, spinforbidden transitions have been observed. The energy difference between the lowest spin-allowed and spin-forbidden n-+ 1r* excitations in ...

Ketone aldehydes in tissues.

Engineering Cofactor Preference of Ketone Reducing Biocatalysts: A Mutagenesis Study on a γ-Diketone Reductase from the Yeast Saccharomyces cerevisiae Serving as an Example

The synthesis of pharmaceuticals and catalysts more and more relies on enantiopure chiral building blocks. These can be produced in an environmentally benign and efficient way via bioreduction of prochiral ketones catalyzed by dehydrogenases. A productive source of these biocatalysts is the yeast Saccharomyces cerevisiae, whose genome also encodes a reductase catalyzing the sequential reduction...

das g?ttliche aus der sicht rumis und der romantiker

die kultur eines jeden landes kann als ein nicht in sich abgeschlossenes system angesehen werden, das durch das handeln der menschen, durch anpassung, ubernahme, bereicherung etc. mit unterschiedlichem grad der dynamik, st?ndig im wandel ist. als eine ihrer auspr?gungen, werden in der literatur verschiedener kulturkreise die interkulturellen gemeinsamkeiten deutlich sichtbar. der ursprung vorha...