Chemistry of 1-Fluoro-2,3,4-triphenylcyclobutadiene Dimers (2007)
Choudhury, Angshuman R, Chopra, Deepak, Guru Row, Tayur N, Nagarajan, Kuppuswamy, Roberts, John D
The reaction of 2,4-dichloro-1,1-difluoro-3-phenyl-2-cyclobutene 1 with excess phenyllithium and subsequent transformations of the products have been reinvestigated. The phenyllithium reaction...
SMALL-RING COMPOUNDS. XLI. THE FORMOLYSIS OF ALLYLCARBINYL TOSYLATE, (2006)
Servis,Kenneth L., Roberts,John D.
Allylcarbinyl tosylate was found to solvolyze in 98% formic acid 3.7 times faster than n-butyl tosylate. Changes in the rate ratio with nucle ophilicity of the solvent suggests different mechanisms...
Pople, Schneider, and Bernstein - A truly seminal treatise of NMR (2005)
The appearance of the authoritative and comprehensive book, High-Resolution Nuclear Resonance Spectroscopy, by John A. Pople, William G. Schneider, and Harold J. Bernstein in 1959 came at just the...
Health related quality of life in sickle cell patients: The PiSCES project (2005)
McClish, Donna K, Penberthy, Lynne T, Bovbjerg, Viktor E, Roberts, John D, Aisiku, Imoigele P, Levenson, James L, ...
Abstract Background Sickle cell disease (SCD) is a chronic disease associated with high degrees of morbidity and increased mortality. Health-related quality of life (HRQOL) among adults with sickle...
Whitesides,George M., Holtz,David, Roberts,John D.
The difference in chemical shift between the methylene protons of a number of compounds related structurally to 1-phenylethyl benzyl ether has been measured. Correlations between structural features...
NITROGEN-15 MAGNETIC RESONANCE SPECTROSCOPY III. (2005)
Lambert,Joseph B., Roberts,Bryan W., Binsch,Gerhard, Roberts,John D.
Certain studies utilizing N15-MR techniques are reviewed and areas for future investigations are suggested.
Lambert, Joseph B., Roberts, John D.
The temperature dependence of the geminal fluorine-fluorine chemical-shift differences in a variety of unsymmetrically substituted cyclobutanes is interpreted in terms of a classical equilibrium...
NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY. LONG-RANGE SPIN COUPLINGS IN VINYLACETYLENE (2005)
SNYDER,EUGEN I., ALTMAN,L.J., ROBERTS,JOHN D.
Theoretical couplings discussions must take into account the fact that the couplings are by no means negligibly small. This is clearly illustrated by the n.m.r. spectrum of the acetylenic proton of...
RELATIVE SIGNS OF THE (31)P-(1)H AND (31)P-C-(1)H NMR COUPLINE CONSTANTS, (2005)
Whitesides ,George M., Beauchamp ,Jessel, Roberts,John D.
The possibility that terms other than Fermi con tact interaction make significant contributions to nuclear spin-spin coupling with heavy nuclei has stimulated considerable interest in the nmr spectra...
STEREOCHEMICAL ASPECTS OF THE DIELS-ALDER REACTION, (2005)
Lambert, Joseph B., Roberts, John D.
In the Diels-Alder reaction of hexachlorocyclopentadiene and alpha-methyl-styrene, the cistrans ratio of deuterium in the beta-position of the alkene remains unchanged in the adduct. The reactions of...
Studies of the nuclear magnetic resonance of ethyl groups are being conducted. The spectra of acetaldehyde diethyl acetal (I) and diethyl sulfite (II) are discussed as examples of magnetic...
Lambert, Joseph B., Roberts, John D.
The imine protons of nitrogen-15 labeled ketimines exhibit temperature-dependent nuclear magnetic resonances. Analysis of the effect of concentration of substrate on the mean lifetime indicates that...
NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY: ANALYSIS OF THE PROTON SPECTRUM OF CYCLOBUTENE. (2005)
Borcic,Stanko, Roberts,John D.
A complete analysis of the proton n.m.r. spectrum of cyclobutene (I) was made which shows that the couplings between the allylic and vinylic protons, while small, are by no means negligible. The...
NITROGEN-15 MAGNETIC RESONANCE SPECTROSCOPY. V. OXYGEN-NITROGEN COMPOUNDS. (2005)
Lambert, Joseph B., Roberts, John D.
The N-15 chemical shifts of a series of oxygennitrogen compounds were found to vary over a range of 576 p.p.m. Since the calculated range of the diamagnetic contribution is only 80 p.p.m., the...
LONG RANGE NUCLEAR SPIN-SPIN COUPLING. ALLENIC AND POLYACETYLENIC SYSTEMS (2005)
SNYDER,EUGENE I., ROBERTS,JOHN D.
A study was made to determine the magnitude and sign of coupling constants in allenic derivatives and to investigate some saturated systems for which significant super long-range coupling constants...
Whitesides, George M., Roberts, John D.
Qualitative and semi-quantitative examination of the temperature dependence of the RCH2-Mg proton n.m.r. spectra of several Grignard reagents indicates that the rate of inversion at this center is...
Quantum-mechanical calculations of the stabilities of fluxional isomers of C4H7+ in solution (2003)
Casanova, Joseph, Roberts, John D.
Although numerous quantum calculations have been made over the years of the stabilities of the fluxional isomers of C4H7+, none have been reported for other than the gas phase (which is unrealistic...
Integration of an Internet Attack Simulator in an HLA Environment (2000)
John R. Mostow, John D. Roberts, John Bott
: A Tactical Internet (TI) comprising the components of the communications infrastructure needed to support future multimedia information requirements will be a key component of the systems...
Diau, Eric W.-G., Casanova, Joseph, Roberts, John D., Zewail, Ahmed H.
In this communication, we report our femtosecond real-time observation of the dynamics for the three didehydrobenzene molecules (p-, m-, and o-benzyne) generated from 1,4-, 1,3-, and...
LONG-RANGE PROTON SPIN-SPIN COUPLING IN DIMETHYL SULFONE, (1998)
Whitesides, George M., Roberts, John D.
A wide variety of chemical and spectral data suggest that a sulfone group is capable of interaction with an adjacent unsaturated center; however, it seems possible that the mode of this interaction...
CONFORMATIONAL BARRIERS IN MEDIUM-SIZED RINGS. I. TRANS-CYCLODECENE-1,2,4,4,9,9-D6. (1998)
Binsch, Gerhard, Roberts, John D.
The peculiar conformational situation in transcycloalkenes of medium rign size is discussed. It is concluded that one pair of optical isomers should exist in the odd-membered rings and two such pairs...
Lambert, Joseph B., Roberts, John D.
The observation of substantial temperature variations of vicinal hydrogen-fluorine coupling constants in a series of cyclobutanes is consistent with the existence of an equilibrium between...
NITROGEN-15 MAGNETIC RESONANCE SPECTROSCOPY. VI. PYRIMIDINE DERIVATIVES, (1998)
Roberts, Bryan W., Lambert, Joseph B., Roberts, John D.
Proton and nitrogen-15 magnetic resonance spectra of several derivatives of pyrimidine have been studied. Long-range (15)N-H couplings were observed in uracil-(15)N2, 2,4-dichloropyrimidine-(15)N2,...
NITROGEN-15 MAGNETIC RESONANCE SPECTROSCOPY. II. COUPLING CONSTANTS. (1998)
Binsch,Gerhard, Lambert,Joseph B., Roberts,Bryan W., Roberts,John D.
Coupling constants were measured between nitrogen-15 and directly bonded hydrogen or carbon-13, and between nitrogen-15 and hydrogen separated by two or more bonds. The data may generally be...
Grocki,John J., Holta,David, Steinberg,Herbert, Roberts,John D.
The chemical shift between the geminal methylene protons of 1-phenylethyl benzyl ether was measured in a variety of solvents. An approximate correlation observed between solvent dielectric constant...
NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY. STUDIES OF 1, 1, 4, 4-TETRAFLUORO-1, 3-ALKADIENES. (1998)
Servis,Kenneth L., Roberts,John D.
1, 1, 4, 4-Tetrafluoro-1, 3-butadiene is indicated by dipole-moment studies to exist in the s-trans conformation. The F19-F19 spin-spin couplings constants for this compound are surprisingly similar...
Gwynn,Donald E., Whitesides,George M., Roberts,John D.
The fluorine n.m.r. spectrum of fluorocyclooctatetraene has been shown to be temperature dependent between 30C and -65C. This is attributed to changes in the rate of an inversion-bond shift process...
Kanamori, Keiko, Weiss, Richard L., Roberts, John D.
The efficiency factor, the number of moles of ATP generated per mole of glucose fermented, was determined in anaerobic, non-carbon-limited N2-fixing cultures of Bacillus polymyxa, Bacillus macerans,...
Kanamori, Keiko, Weiss, Richard L., Roberts, John D.
Pathways of ammonia assimilation into glutamic acid were investigated in ammonia-grown and N2-fixing Clostridium kluyverii and Clostridium butyricum by measuring the specific activities of glutamate...
Glutamate biosynthesis in Bacillus azotofixans. 15N NMR and enzymatic studies (1988)
Kanamori, Keiko, Weiss, Richard L., Roberts, John D.
Pathways of ammonia assimilation into glutamic acid in Bacillus azotofixans, a recently characterized nitrogen-fixing species of Bacillus, were investigated through observation by NMR spectroscopy of...
Role of glutamate dehydrogenase in ammonia assimilation in nitrogen-fixing Bacillus macerans (1987)
Kanamori, Keiko, Weiss, Richard L., Roberts, John D.
Pathways of ammonia assimilation into glutamic acid in Bacillus macerans were investigated by measurements of the specific activities of glutamate dehydrogenase (GDH), glutamine synthetase, and...
Ammonia assimilation in Bacillus polymyxa. 15N NMR and enzymatic studies (1987)
Kanamori, Keiko, Weiss, Richard L., Roberts, John D.
Pathways of ammonia assimilation into glutamic acid and alanine in Bacillus polymyxa were investigated by 15N NMR spectroscopy in combination with measurements of the specific activities of glutamate...
Kanamori, Keiko, Legerton, Timothy L., Weiss, Richard L., Roberts, John D.
The influences of different nitrogen sources on the relative rates of biosynthesis of glutamine and alanine have been studied by 15N nuclear magnetic resonance spectroscopy of intact Neurospora...
15N NMR study of a mixture of uniformly labeled tRNAs (1982)
Gonnella, Nina C., Birdseye, Theresa R., Nee, Michael, Roberts, John D.
15N NMR spectra were taken of 15N-enriched tRNA extracted from bakers yeast; ammonium sulfate was used as a nitrogen source. The increase in the degree of denaturation of tRNA, which occurs with...
Determination of current distribution patterns in electrically stimulated tissue specimens / (1982)
Thesis (M.S.)--Kansas State University, 1982.
Thesis (M.S.)--Kansas State University, 1982.
Bachovchin, William W., Kaiser, Robert, Richards, John H., Roberts, John D.
L-Histidine, 90% 13C enriched at the C2 position, was incorporated into the catalytic triad of alpha-lytic protease (EC 3.4.21.12) with the aid of a histidine-requiring mutant of Lysobacter...
15N NMR Studies of Nitrogen Metabolism in Intact Mycelia of Neurospora crassa (1981)
Legerton, Timothy L., Kanamori, Keiko, Weiss, Richard L., Roberts, John D.
Suspensions of intact mycelia of Neurospora crassa grown in medium containing 15NH4Cl have been found to give well-resolved 15N nuclear magnetic resonance spectra for metabolites that play crucial...
Dyllick-Brenzinger, Christina, Sullivan, Glenn R., Pang, Patty P., Roberts, John D.
The self-association of guanosine, cytidine, and adenosine and base pairing between guanosine, cytidine, adenosine, and uridine in dimethyl sulfoxide have been investigated by the variation of their...
Roberts, John D., Kanamori, Keiko
The acceleration, by a factor of 2500, of the hydrolysis of endo-5-[4'(5')imidazolyl]bicyclo[2.2.1]hept-endo-2-yl trans-cinnamate by 0.5 M sodium benzoate in 42 mol% dioxane in water can be explained...
Botto, Robert E., Schwartz, Joseph H., Roberts, John D.
The 13C and 15N chemical shifts of five N-arylguanidinium chlorides carrying polar substituents, ranging in character from 4-methoxy to 4-nitro groups, have been determined by NMR spectroscopy at the...
Basic Principles of Organic Chemistry, second edition (1977)
Roberts, John D., Caserio, Marjorie C.
PREFACE: No period in the history of organic chemistry has been as dynamic and productive of research accomplishment as the twelve years between the completion of the first and present editions of...
Nitrogen-15 nuclear magnetic resonance of aliphatic tripeptides (1977)
Markowski, Volker, Posner, Tamar B., Loftus, Philip, Roberts, John D.
The 15N chemical shifts of eight aliphatic tripeptides have been measured at the natural-abundance level. For a given tripeptide, the resonances of the COOH-terminal and NH2-terminal amino acids can...
Gust, Devens, Moon, Richard B., Roberts, John D.
Natural-abundance nitrogen-15 nuclear magnetic resonance spectroscopy of enzymes and other biopolymers is found to be feasible using newly available instrumentation. The long correlation times of...
Pearson, Harry, Gust, Devens, Armitage, Ian M., Huber, Hanspeter, Roberts, John D., Stark, Ruth E., ...
The carbon-13 spin-lattice relaxation times (T1) of glycine have been measured as a function of pD and concentration. Contrary to previously reported findings, no significant dependence was observed...
Giannini, Donald D., Chan, Kenneth K., Roberts, John D.
Carbon-13 nuclear magnetic resonance spectra have been obtained for the coumarin-related compounds warfarin and phenprocoumon. The spectral assignments indicate that warfarin exists as a mixture of...
Química Orgánica. De Metano a Macromoléculas (1974)
Traducción de: Organic Chemistry: Methane to Macromolecules
Química Orgánica. De Metano a Macromoléculas (1974)
Traducción de: Organic Chemistry: Methane to Macromolecules
Hawkins, Bruce L., Roberts, John D.
Carbon-13 nuclear magnetic resonance spectra have been taken of Δ8- and Δ9-tetrahydrocannabinol. The absorptions have been assigned to specific carbons with the aid of off-resonance and selective...
Johns, S. R., Smith, Robert A., Hawkes, Geoffrey E., Roberts, John D.
The pattern of 13C and 1H nuclear magnetic resonance (NMR) shift changes produced by complexation of cobalt and nickel acetylacetonates with amines and alcohols indicates that there is more than one...
Marzin, Claude, Leibfritz, Dieter, Hawkes, Geoffrey E., Roberts, John D.
Lanthanide-induced shifts of 13C nuclear magnetic resonances are reported for several amines and n-butyl isocyanide. Contact contributions to such shifts, especially of ß carbons, are clearly...
Halgren, Thomas A., Firkins, John L., Fujimoto, T. A., Suzukawa, H. H., Roberts, John D.
Studies of product compositions and deuterium-label rearrangements at various concentrations of tri-n-butyltin hydride in the reductions of exo- and endo-5-bromonorbornene and 2-bromonortricyclene to...
Organic chemistry: methane to macromolecules (1971)
Roberts, John D., Stewart, Ross, Caserio, Marjorie C.
The success achieved by this book's forerunners, Basic Principles of Organic Chemistry and Modern Organic Chemistry, was to a considerable extent due to the rigor with which the subject of organic...
Doddrell, David, Charrier, Claude, Roberts, John D.
The proton-decoupled 13C nmr spectrum of 1,1-difluorocyclohexane has been examined at room temperature and at -90 degrees C. There are only minor changes in the one-bond and two-bond carbon-fluorine...
Doddrell, David, Charrier, Claude, Hawkins, Bruce L., Crain, W.O., Harris, Leland, Roberts, John D.
A variable-temperature, proton noise-decoupled, 13C nmr spectral study of the chair-chair interconversion in 1,1,3,3-tetramethylcyclohexane has demonstrated the utility of 13C spectra for probing...
Natural-Abundance 13C Nuclear Magnetic Resonance Spectra of Terpenes and Carotenes (1970)
Jautelat, Manfred, Grutzner, John B., Roberts, John D.
Natural-abundance 13C nuclear magnetic resonance spectra are reported for some simple terpenes and carotenes. The techniques involved in the assignment of the resonances to specific carbons are...
Nuclear magnetic resonance spectroscopy: 13C spectra of some common nucleotides (1970)
Dorman, Douglas E., Roberts, John D.
Natural-abundance 13C nuclear magnetic resonance spectra of ten common nucleotides in neutral, aqueous solutions have been determined and interpreted. The spectra of two of these substances were also...
Cálculos con orbitales moleculares (1969)
Traducción de: Notes on Molecular Orbital Calculations
Cálculos con orbitales moleculares (1969)
Traducción de: Notes on Molecular Orbital Calculations
Weigert, Frank J., Jautelat, Manfred, Roberts, John D.
The difficulties in detection of C13 magnetic resonance signals in organic compounds which arise from the low natural abundance and the small magnetic moment of C13 are well known [1]. For complex...
Nitrogen-15 magnetic resonance spectroscopy, I. Chemical shifts (1964)
Lambert, Joseph B., Binsch, Gerhard, Roberts, John D.
Except for the original determination(1) of nuclear moments, nitrogen magnetic resonance spectroscopy has been limited to the isotope of mass number 14. Although N14 is an abundant isotope, it...
Whitesides, George M., Kaplan, Fred, Nagarajan, K., Roberts, John D.
The protons of a methylene group removed by one or more bonds from a center of molecular asymmetry may be magnetically nonequivalent and display AB-type nuclear magnetic resonance (n.m.r.) spectra...
Notes on Molecular Orbital Calculations (1961)
From the Preface: For practicing organic chemists the simple, linear-combination-of-atomic-orbitals (LCAO), molecular-orbital method permits useful calculations of semi-empirical electronic energies...
Shafer, Paul R., Davis, Donald R., Vogel, Martin, Nagarajan, K., Roberts, John D.
Nuclear magnetic resonance (n.m.r.) spectroscopy provides an excellent means for qualitative identification of ethyl groups by use of the familiar three-four pattern of spin-spin splitting (1). It...
From the preface: To learn to apply the methods of wave mechanics in a practical way seems to involve a quantum-like transition with a relatively low transition probability. Chemistry students by the...
Notes on molecular orbital calculations / John D. Roberts (1961)
Segunda impresión corregida
Nuclear Magnetic Resonance: applications to organic chemistry (1959)
From the preface: This brief book is the outgrowth of some forty lectures in which it was attempted to explain the phenomenon of nuclear magnetic resonance absorption and the uses of high-resolution...
Diau, Eric W.-G., Casanova, Joseph, Roberts, John D., Zewail, Ahmed H.
In this communication, we report our femtosecond real-time observation