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Articles 1 - 13 of 13
Full-Text Articles in Physical Sciences and Mathematics
Kinetic And Mechanistic Studies Of The Deuterium Exchange In Classical Keto−Enol Tautomeric Equilibrium Reactions, Michael Nichols, Mark Waner
Kinetic And Mechanistic Studies Of The Deuterium Exchange In Classical Keto−Enol Tautomeric Equilibrium Reactions, Michael Nichols, Mark Waner
Michael A Nichols
An extension of the classic keto−enol tautomerization of β-dicarbonyl compounds into a kinetic analysis of deuterium exchange is presented. It is shown that acetylacetone and ethyl acetoacetate undergo nearly complete deuterium exchange of the α-methylene carbon when dissolved in methanol-d4. The extent of deuteration may be monitored via NMR spectroscopy as a function of time. A mechanism for deuterium exchange is presented and shown to be consistent with a consecutive first-order process. The data for acetylacetone are consistent with steady-state kinetics, whereas those of ethyl acetoacetate illustrate nonsteady-state behavior, offering an accessible example where students might collect and analyze real …
Synthesis Of [15n,15n‘]-N,N,N‘,N‘-Tetramethyl- Ethylenediamine And Its Use In Solvation Studies Of [6li]-N-Butyllithium., Delia Waldmüller, Barbara Kotsatos, Michael Nichols, Paul Williard
Synthesis Of [15n,15n‘]-N,N,N‘,N‘-Tetramethyl- Ethylenediamine And Its Use In Solvation Studies Of [6li]-N-Butyllithium., Delia Waldmüller, Barbara Kotsatos, Michael Nichols, Paul Williard
Michael A Nichols
No abstract provided.
Purification And Crystallization Of Cyclin-Dependent Kinase Inhibitor P21., D. Mayrose, Michael Nichols, Y. Xiong, H. Ke
Purification And Crystallization Of Cyclin-Dependent Kinase Inhibitor P21., D. Mayrose, Michael Nichols, Y. Xiong, H. Ke
Michael A Nichols
p21, a universal inhibitor of mammalian cyclin-dependent kinases (CDK), regulates cell cycle progression by forming various distinct protein complexes with cyclins, CDKs, and the proliferating cell nuclear antigen. We have overexpressed recombinant human p21 in E. coli and purified active p21 to near homogeneity on a large scale. Crystals of recombinant p21 have been grown in the space group P2(1) a = 157.4, b = 152.7, c = 90.6 A, and beta = 92.7 degrees. The diffraction data of the recombinant p21 have been collected to 2.5 and 3.5 A resolution for the native crystal and two heavy atom derivatives …
6li And 15n Nuclear Magnetic Resonance Studies Of Mixed Alkali Metal Cation Hexamethyldisilazide Bases, Michael Nichols, Delia Waldmüller, Paul Williard
6li And 15n Nuclear Magnetic Resonance Studies Of Mixed Alkali Metal Cation Hexamethyldisilazide Bases, Michael Nichols, Delia Waldmüller, Paul Williard
Michael A Nichols
No abstract provided.
Hexameric Lithium Phenolate: Crystal Structures And Lithium-7 Quadrupole Coupling In Solid And Solution Phases., Lloyd Jackman, Deniz Cizmeciyan, Paul Willard, Michael Nichols
Hexameric Lithium Phenolate: Crystal Structures And Lithium-7 Quadrupole Coupling In Solid And Solution Phases., Lloyd Jackman, Deniz Cizmeciyan, Paul Willard, Michael Nichols
Michael A Nichols
No abstract provided.
Solid-State Structures Of N-Butyllithium-Tmeda, -Thf, And -Dme Complexes., Michael Nichols, Paul Williard
Solid-State Structures Of N-Butyllithium-Tmeda, -Thf, And -Dme Complexes., Michael Nichols, Paul Williard
Michael A Nichols
No abstract provided.
Synthesis And Structure Of A Product, Formed During Dna Nicking With A Cyclometallated Nuclease, Consisting Of An Adenine Bridging Two Palladium(Ii) Complexes., J. Suggs, Michael Du\Ube, Michael Nichols
Synthesis And Structure Of A Product, Formed During Dna Nicking With A Cyclometallated Nuclease, Consisting Of An Adenine Bridging Two Palladium(Ii) Complexes., J. Suggs, Michael Du\Ube, Michael Nichols
Michael A Nichols
Journal of the Chemical Society, Chemical Communications
Γ-Aminobutyric Acid, Catecholamine And Indoleamine Determinations From The Same Brain Region By High-Performance Liquid Chromatography With Electrochemical Detection., T. Champney, W. Hanneman, Michael Nichols
Γ-Aminobutyric Acid, Catecholamine And Indoleamine Determinations From The Same Brain Region By High-Performance Liquid Chromatography With Electrochemical Detection., T. Champney, W. Hanneman, Michael Nichols
Michael A Nichols
A new procedure for the measurement of γ-aminobutyric acid, norepinephrine, dopamine, serotonin and 5-hydroxyindoleacetic acid from the same brain region was developed. In general, two separate high-performance liquid chromatographic runs were performed, one for the γ-aminobutyric acid determination and one for the determination of the monoamines. The electrochemical detection of γ-aminobutyric acid was determined by a new procedure that utilized a small aliquot of the brain sample prepared for monoamine measurement. This assay was linear and parallel between 6 and 200 ng per 20-μl injection with 5-aminovaleric acid utilized as an internal standard. Inter-assay variability averaged 5% throughout the assay …
Structural Characterization Of Mixed Alkali Metal Bis(Trimethylsilyl)Amide Bases., Paul Williard, Michael Nichols
Structural Characterization Of Mixed Alkali Metal Bis(Trimethylsilyl)Amide Bases., Paul Williard, Michael Nichols
Michael A Nichols
No abstract provided.
Chelation Of 2-Substituted 1-Lithoxides: Structural And Energetic Factors Of Relevance To Synthetic Organic Chemistry., Michael Nichols, Andrew Mcphail, Edward Arnett
Chelation Of 2-Substituted 1-Lithoxides: Structural And Energetic Factors Of Relevance To Synthetic Organic Chemistry., Michael Nichols, Andrew Mcphail, Edward Arnett
Michael A Nichols
No abstract provided.
Structural And Energetic Evidence For Oxygen-Lithium-Nitrogen Chelation In A Model For Asymmetric Induction., Edward Arnett, Michael Nichols, Andrew Mcphail
Structural And Energetic Evidence For Oxygen-Lithium-Nitrogen Chelation In A Model For Asymmetric Induction., Edward Arnett, Michael Nichols, Andrew Mcphail
Michael A Nichols
No abstract provided.
Structure-Energy Relations For The Aldol Reaction In Nonpolar Media., Edward Arnett, Franklin Fisher, Michael Nichols, Anthony Ribeiro
Structure-Energy Relations For The Aldol Reaction In Nonpolar Media., Edward Arnett, Franklin Fisher, Michael Nichols, Anthony Ribeiro
Michael A Nichols
No abstract provided.
Thermochemistry Of A Structurally Defined Aldol Reaction., Edward Arnett, Franklin Fisher, Michael Nichols, Anthony Ribeiro
Thermochemistry Of A Structurally Defined Aldol Reaction., Edward Arnett, Franklin Fisher, Michael Nichols, Anthony Ribeiro
Michael A Nichols
No abstract provided.