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Showing 1 to 20 of 33 for “"reactive intermediate"”.
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Mechanistic and spectroscopic methods for identifying reactive intermediate structures and active site properties over metals, metal oxides, and metal phosphides
… order to improve the design of highly selective, reactive, cost effective, and stable catalysts. In situ characterization methods provide the ability to correlate different catalyst properties (e.g., surface acidity, hydrophobicity, cluster size) under reaction conditions with changes in rates and …
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Chemometric methods for the analysis of process spectra using minimal reference data
… may occur. If the reaction proceeds via a reactive intermediate or affords a reactive product, isolated reference standards of those species may not be available. Reactions in industry are often heterogeneous and highly concentrated; sampling the batch throughout the course of the reaction …
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Development and Investigation of a Dehydrative Glycosylation With Activated Diphenyl Sulfonium Reagents
… Additional data suggests, however, that the reactive intermediate is likely a glycosyl oxocarbenium.
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Melatonin's Protection against DNA Damage by the Iron (III)-Adriamycin Complex.
… oxidatively cleaves DNA via the generation of reactive oxygen species (ROS). Enzymes associated specifically with heart mitochondria increase ROS formation explaining why adriamycin is selectively cardiotoxic. Pretreatment of mice with the neural hormone melatonin eliminates the cardiotoxic …
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The photochemistry of 2,4- and 2,6-cyclo-octadienone
… In methanol and furan, however, capture of a reactive intermediate in the photolysis occurred much more rapidly than intramolecular rearrangement. This reactive intermediate was detected by using low temperature photolysis techniques to involve a strained ground state trans intermediate. …
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The oxidation of secondary alcohols by dipotassium tetraoxoferrate (VI) In concentrated and dilute potassium hydroxide solutions
… oxygen evolution was 3/2 order· in some reactive intermediate, other than iron-VI. Deuterium isotope effects show that the breaking of the C-1! bond on the alpha-carbon is the rate determining step for the oxidation. The isotope effects also indicate, by applying the Swain Criteria, that …
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Spectroscopic characterization of iron-oxygen intermediates in human aromatase (CYP19A1)
… known as “Compound 1” in P450 chemistry is the reactive intermediate that catalyzes most of the reactions of P450s. The identity of the reaction intermediate that catalyzes the terminal step estrogen biosynthesis by CYP19A1 is still a mystery. There is evidence in the literature suggesting the …
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The fluroxene mediated degradation of cytochromes P-450
… degradation of cytochromes P-450 by fluroxene, a reactive species is proposed to be involved. By varying the experimental conditions, and with the use of inhibitors of cytochromes P-450, the likely sequence of events in the fluroxene mediated degradation of cytochromes P-450 is shown to be as …
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Memory of Chirality in 1,4-Benzodiazepin-2-ones
… chemistry, reactions involving carbocation intermediates, and to radical systems. In this strategy the chirality of an enantiopure reactant is transferred to the dynamic chirality of a reactive intermediate to produce stereospecific product. 1,4-Benzodiazepin-2-ones have been described as a …
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The kinetics of the arsenic(III) - chromium(VI) reaction on acetic acid-acetate buffers
… with the formation of tetravalent chromium as-a reactive intermediate. The stoichiometry or the overall reaction was found to be 3 As(III) + 2 Cr(VI) = 3 Aa(V) + 2 Cr(III).
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Experimental and Computational Studies in Bioorganic and Synthetic Organic Chemistry
… synthesis in which the dynamic chirality of the reactive intermediate "memorizes" the static chirality of the reactant. Using dynamic 1D and 2D NMR and density functional theory (DFT) methods, we studied the MOC effect of 1,4-benzodiazepin-2-ones. Reconstruction of the reaction pathway using DFT …
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Reductive Alkylation Reactions Using Tetramethyldisiloxane and Potassium Tert-Butoxide Via Reductive-Radical Polar Crossover
… polar characteristic of the benzyl nucleophile reactive intermediate, proving the system undergoes the process of reductive-radical polar crossover (RRPC) Ultimately, the TMDSO and KOtBu reagent pair is thought to be synthetically useful in performing reactions in transition-metal-, photoredox-, …
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Direct synthesis of pyridine and pyrimidine derivatives
… anhydride followed by nitrile addition into the reactive intermediate and cycloisomerization. In situ nitrile generation from primary amides allows for their use as nitrile surrogates. The use of this chemistry with sensitive N-vinyl amides and epimerizable substrates in addition to a wide range …
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Strategies for the synthesis of bioactive compounds: biomimetic approaches to the Salinosporamides and the hexadehydro-Diels-Alder reaction
… between a diyne and an alkyne to form aryne reactive intermediate. In Part II we show the scope of substrates that are capable of generating an aryne via the HDDA reaction. Additionally, we show that HDDA-mediated generation of arynes allows for the discovery of new modes of aryne trapping, …
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Structural studies of rebeccamycin, staurosporine, and violacein biosynthetic enzymes
… pathways diverge at two steps, each involving a reactive, bisindole intermediate. We have taken a structural approach to characterize the biosynthetic enzymes responsible for these divergence points in each pathway. One major difference between rebeccamycin and staurosporine is the oxidative …
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Mechanistic aspects of thiamine biosynthesis in escherichia coli
… anaerobic bacteria (such as Escherichia coli) a reactive intermediate, dehydroglycine, required for the biosynthesis of the thiazole moiety is derived from cleavage of the C??C? bond of tyrosine in a reaction catalysed by the radical S-adenosyl-L-methionine (SAM) enzyme, tyrosine lyase (ThiH). …
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Understanding the mechanism of androgen biosynthesis
… key questions regarding the nature of the reactive intermediate responsible for androgen formation have heretofore remained unanswered. Specifically, while the hydroxylase activity of CYP17A1 is expected to proceed through standard P450 ferryl-oxene intermediate, identity of the iron-oxygen …
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Dioxycarbenes and 3,3-Dioxyvinylcarbenes in the Synthesis of Novel Heterocycles
… Recently, the intramolecular cyclization of reactive intermediates, such as anions, cations, and radicals have provided a number of new methods by which known and novel ring systems can be constructed. Cyclizations involving tandem, or multiple sequences have gained considerable popularity …
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Synthetic Studies of the Rubellin Natural Products
… our investigation of a rearrangement reaction of reactive iodonium ylide intermediates. First described are select syntheses of complex anthraquinone monomers and dimers within the past 20 years. The scientific community has found deep interest in the anthraquinone class of compounds due to their …
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