نتایج جستجو برای: ketones
تعداد نتایج: 9200 فیلتر نتایج به سال:
Although considerable attention has been given to the identification of keto acids produced during the fermentation of glucose by Escherichia coli, relatively little information has been obtained on the production of aldehydes and ketones. During an investigation of the keto acids produced during glucose fermentation by E. coli 82/r and P6 (D. W. Thayer and J. E. Ogg, Bacteriol. Proc., p. 96, 1...
Bromination of aralkyl ketones using N-bromosuccinimide in presence of active Al2O3 provided either α -monobrominated products in methanol at reflux or mononuclear brominated products in acetonitrile at reflux temperature with excellent isolated yields depending on the nature of substrate employed. The α -bromination was an exclusive process when aralkyl ketones containing moderate activating/d...
The Brønsted-acidic ionic liquid 1-methyl-3-(4-sulfobutyl)imidazolium triflate [BMIM(SO(3)H)][OTf] was demonstrated to act efficiently as solvent and catalyst for the halogenation of activated organic compounds with N-halosuccinimides (NXS) under mild conditions with short reaction times. Methyl aryl ketones were converted into α-halo and α,α-dihaloketones, depending on the quantity of NXS used...
The inhibitory effects of alkyl phenyl ketones on carbonyl reductase activity were examined in pig heart. In this study, carbonyl reductase activity was estimated as the ability to reduce 4-benzoylpyridine to S(-)-alpha-phenyl-4-pyridylmethanol in the cytosolic fraction from pig heart (pig heart cytosol). The order of their inhibitory potencies was hexanophenone > valerophenone > heptanophenone...
Based on recent work demonstrating age-dependent ketogenic neuroprotection after traumatic brain injury (TBI), it was hypothesized that the neuroprotection among early post-weaned animals was related to induced cerebral transport of ketones after injury. Regional changes in monocarboxylate transporter 2 (MCT2) were acutely examined with immunohistochemistry after sham surgery or controlled cort...
The efforts for synthesis of enantiomerically pure bis-(1,2,3-triazolylmethyl)amino esters 6 are reported in good yields from an in situ generated α-azidomethyl ketone. Optimum experimental conditions were established for preparation of α-halomethyl ketones 10 and α-N,N-dipropargylamino esters 11, all derived from α-amino acids. The starting materials reacted under conventional click chemistry ...
Alpha-Hydroxy ketones with an aromatic and aliphatic substituent were prepared with condensation of aromatic and aliphatic aldehydes in the presence of polymer-bound thiazolium salt.
Catalytic enantioselective methods for the preparation of chiral azaarene-containing compounds are of high value. By combining the utility of copper hydride catalysis with the ability of C═N-containing azaarenes to activate adjacent alkenes toward nucleophilic additions, the enantioselective reductive coupling of alkenylazaarenes with ketones has been developed. The process is tolerant of a wid...
The direct β-activation of saturated aldehydes and ketones has long been an elusive transformation. We found that photoredox catalysis in combination with organocatalysis can lead to the transient generation of 5π-electron β-enaminyl radicals from ketones and aldehydes that rapidly couple with cyano-substituted aryl rings at the carbonyl β-position. This mode of activation is suitable for a bro...
Visible light photoredox/nickel dual catalysis has been employed in the cross-coupling of acyl chlorides with potassium alkyltrifluoroborates. This protocol, based on single-electron-mediated alkyl transfer, circumvents the restriction of using reactive alkylmetallic nucleophiles in transition-metal-catalyzed acylation and achieves a mild and efficient method for the synthesis of unsymmetrical ...
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