نتایج جستجو برای: ketones
تعداد نتایج: 9200 فیلتر نتایج به سال:
Baeyer-Villiger monooxygenases (BVMOs) are extremely promising catalysts useful for enantioselective oxidation reactions of ketones, but organic chemists have not used them widely due to several reasons. These include instability of the enzymes in the case of in vitro and even in vivo systems, reactant/product inhibition, problems with upscaling and the necessity of using specialized equipment....
The Pictet-Spengler reaction (PSR) involves the condensation and ring closure between a β-arylethylamine and a carbonyl compound. The combination of dopamine and ketones in a PSR leads to the formation of 1,1'-disubstituted tetrahydroisoquinolines (THIQs), structures that are challenging to synthesize and yet are present in a number of bioactive natural products and synthetic pharmaceuticals. H...
Enantioselective hydrogenation of amino ketones catalyzed by Ru– or Rh–phosphine complexes provides an efficient method for the synthesis of enantiomerically active amino alcohols, a class of chiral compounds of great importance in pharmaceutical products. A recent challenging target inspired us to look for a practical solution for the enantioselective reduction of b-amino ketones with a second...
In present communication a novel series of benzodiazepine derivatives were synthesized from α, β-unsaturated ketones and evaluated for their antimicrobial activities. The α, β-unsaturated ketones were prepared by ClaisenSchimidt Condensation of Indan-1-one with different aldehydes in presence bleaching earth clay and PEG400 as Greener reaction solvent. A novel benzodiazepine derivatives were sy...
Twenty Karakul rams were allotted to four groups, subjected first to starvation and then allowed restricted amounts (approximately 1/3 of ad l ib i tum intake) of a high fiber, low energy diet containing no additive (control), 5% 1,3-butanediol (BD), 10% BD, and 5% 1,2-propanediol (PD) for 6 weeks. Starvation elevated (P<.O01) serum ketones (3-hydroxybutyrate and acetoacetate) and decreased (P<...
Size and shape criteria for guest binding inside the cavity of an octanuclear cubic coordination cage in water have been established using a new fluorescence displacement assay to quantify guest binding. For aliphatic cyclic ketones of increasing size (from C5 to C11), there is a linear relationship between ΔG for guest binding and the guest's surface area: the change in ΔG for binding is 0.3 k...
The dielectric behaviors of some small symmetric ketone molecules, including acetone, 3-pentanone, cyclopentanone, 4-heptanone, and cyclohexanone, were investigated as a function of temperature (T) over a wide frequency range from 50 MHz (3.14 × 10(8) s(-1), in angular frequency) to 3 THz (1.88 × 10(13) s(-1)). The temperature dependencies of the rotational diffusion times (τ(r)) determined usi...
Selective hydrogenation of the carbon-oxygen bond in α,β-unsaturated carbonyl compounds is a synthetic challenge, since C=C bond reduction is thermodynamically more favorable (35 kJ mol–1) than C=O bond reduction.[1] This problem becomes even more complicated by the presence of an aromatic substituent in such systems because of possible ring hydrogenation.[2] Moreover, the transformation of uns...
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