The dielectric relaxation of V₂ 0₅ was investigated using the method of Davidson and Cole. By means of an Argand diagram, deviation from an exact Debye dielectric was established. This was done with the parameter β. For a Debye dielectric β= 1. The largest value of β for V₂O₅ was...
Amphidinolide B₁ is one of the most potent cytotoxic compounds in the
amphidinolide family. Its bioactivity and intriguing structure has drawn
attention from synthetic chemists. Although numerous synthetic efforts toward
the total synthesis of amphidinolide B₁ have been published, it still remains an
unconquered synthetic target.
One of the unique...
The 3-substituded indolic enamide moiety has been found in many marine compounds over the past 20 years. These indolic enamides exhibit various biological properties such as cytotoxic, anthelmintic, antimicrobial and HW-inhibitory activities. Among these indolic enamides, some are (E)-enamides, like coscinamide A and coscinamide B, others are (Z)-configuration in their...
Avermectin Bia is a member of a class of medicinally important
natural products known for its potent antiparasitic activity and
interesting structural features. In this thesis, synthesis of a
model for the spiroketal portion of the avermectins is presented.
Oxidation of (S)-2-methylbutanol, followed by a stereoselective
chromium mediated reaction with...
The structural architecture present in marine toxin azaspiracid - 20 stereocenters, 9 rings, 3 separated spirocenters - has attracted considerable synthetic attention. Our efforts toward the synthesis of azaspiracid have led to the completion of both C₁-C₂₆ northern and C₂₇-C₄₀ southern halves. Herein, the
synthesis of southern FGHI ring system...
Reaction of 4, 6-dimethoxy-5-nitropyrimidine [I], with refluxing
pyridine, was discovered to yield the methylpyridinium salt of
1, 6-dihydr -4-hydroxy-1-methyl-5-nitro-6-oxopyrimidine [III]. Possible
use of I as a general N-methylating agent was explored. No
appreciable reaction occurred between I and refluxing excess n-butyl
alcohol. Similar reaction involving quinoline failed to yield an...
Although 4- and 5-diacetamidopyrimidines have been reported
in the literature within the past eleven years, it was not until 1965
that a 2-diacetamidopyrimidine was reported. The current investigation
was undertaken to determine whether other 2-diacetamidopyrimi-dines could be synthesized and what the effect of various nuclear substituents would be on the...
The enantioselective total synthesis of quinolizidine-containing natural product cermizine D and formal syntheses of senepodine G and cermizine C has been achieved. These natural products are members of the lycopodium alkaloids, which have attracted significant attention due to their exciting biological activities and the diverse structural scaffolds. Key steps in...
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(1) (a) Tanabe, Y.; Uchida, M.; Hasebe, M.; Ito, M. J. Plant. Res. 2003, 116, 71-75. (b)
Matsunga
The use of semi-volatile organic compounds (SOCs) as molecular markers to identify the contributions of regional and long-range atmospheric transport, as well as current and historic sources, and contaminant deposition in remote ecosystems of the Western U.S. was investigated. Trans-Pacific air masses influenced by Siberian biomass burning events had elevated...
Part I: Racemic and asymmetric syntheses of a new substance with prospective antidepressant properties were achieved. In vitro assays with synthetic racemates (±)-25 and (±)-26 suggested that the former is a relatively selective inhibitor of serotonin transporter whereas the latter is a more balanced inhibitor of both serotonin and norepinephrine...
The solution chemistry and kinetic behavior of hafnium peroxy sulfate solutions ("HafSOx") is described in terms of peroxide content and solution speciation. Additionally, thin film behavior, including thermal behavior and solubility, is characterized, and a mechanism of patterning is presented, as well as parameters that should be considered when looking...
The dc conductivity of single crystals of vanadium pentoxide
was measured in the three crystallographic directions. The temperature
range examined was -165°C to +25°C. The activation energy
of the conduction process was isotropic and found to be .56 ev. The
conductivity was anisotropic.
Measurements of the Hall effect were attempted...
Vanadium pentoxide electrodes were prepared by melting
the powdered oxide around a platinum foil in a pyrex tube. The
electrode was discharged, and the discharge product was studied,
but not identified, by means of chemical and x-ray diffraction analysis.
A study was made of the relationship between the electrode
potential...
Vanadium pentoxide single crystals were grown from the melt.
These crystals were made the cathode in an electrolytic cell and the
polarization and recovery of the electrode were studied under a
variety of experimental conditions.
A study of the electrode potential versus that of the standard
hydrogen electrode as a...
A survey of the methods of purification of KC1, for use in
preparing single crystals by growth from the melt, was made. Two
methods, fractional recrystallization and ion exchange, were used.
The purity of the salt and crystals grown from the same salt were
compared with the findings of other...
A systematic study of the elution of magnesium and calcium from
Dowex 50 X 8 resin using α-hydroxyisobutyric acid (α-HIBA) at
various pH values and concentrations, indicated that the difference in
the equilibrium distribution coefficients of these two elements was
large enough for a good separation. This fact was applied...
Quercetin (3, 3', 4', 5, 7-pentahydroxyflavone) reacts with hexavalent
molybdenum, tungsten and chromium to form chelates soluble
in an ethanol-water medium. This color reaction has been investigated
with a view to its possible application in the spectrophotometric
determination of trace amounts of these metals.
In the development of the method,...
The reactions of EGTA, [ethylene bis (oxyethylenenitrilo)]
tetraacetic acid, with 51 metal ions have been studied spectrophotometrically in aqueous solutions.
The absorption spectra of the
chelates formed were measured with a recording spectrophotometer
between 200 and 700 mμ. The pH of each solution was varied and a
spectrum was scanned...
When the dc conductivities of various pure KC1 crystals were
compared it was found that crystals grown under an HC1 atmosphere,
from salt purified by ion exchange, exhibited lower knee temperatures
than any of the crystals studied. These knee temperatures
were found to be approximately 350°C. From this the total...
A dual -pH simultaneous direct spectrophotometric method for
the determination of calcium and magnesium using Arsenazo III has
been developed.
An absorption spectra study was made of Arsenazo III and its
magnesium, calcium, strontium, and barium complexes at various
pH values. This study showed that total calcium and magnesium
can...
Part I of this dissertation includes the chronological synthetic background of mandelalide A as well as the synthesis of the C1-C14 glycosylated southern subunit of mandelalide. A key aspect of the synthesis includes a novel silver-catalyzed cyclization (AgCC) of a propargylic benzoate to construct the substituted cis-pyran ring system present...
The incorporation of europium and dysprosium in potassium
chloride crystals was investigated. The crystals were prepared by
the Kyropoulos method from melts containing the rare-earth chlorides.
The concentration of these rare-earth ions in the crystals was determined
by neutron-activation analysis. The distribution coefficient of
europium and dysprosium between the molten...
The object of this investigation was to determine a number of
physical constants for the crystals of two commonly used insecticide
compounds. The compounds chosen were Aldrin and Dieldrin,
which are chlorinated cyclodiene compounds. These compounds are
in considerable use today, and show promise of heavy continued use.
The data...
Direct current conductivity measurements on KC1:O[superscript]= crystals
were used to determine an enthalpy of 0.42 ev for the dissociation for
anion-vacancy-oxide ion complex.
The entropy of dissociation was
found to be approximately -4x 10⁻⁴ev deg⁻¹. The intrinsic "activation" energy was found to be 1.91 ev as compared to 1.95 ev,...
A simultaneous direct spectrophotometric method for the determination
of barium and strontium using Sulfonazo III has been developed
making use of the chelons EGTA and CDTA at controlled pH
values.
An absorbance study of the barium and strontium complexes of
Sulfonazo III revealed that there is no pH sensitivity of...
The hydroxide ion as a substitutional defect in KC1 can be photo-dissociated
at liquid nitrogen temperature by ultraviolet light. The
photochemistry of this system was investigated by EPR and optical absorption
methods. Theoretical calculations were also performed in an
investigation of the KC1:OH system.
The bleaching behavior of photochemically colored...
The photochemical reaction between O⁻ ions and F centers
was investigated. The activation energy was determined by the
Arrhenius law to be 0.10 + 0.04 eV for temperature below 180°K.
The diffusion of alpha centers towards the oxide ion was eliminated
as the rate limiting step and the low trapping...
The reaction of certain purin-8-ols with phosphorus
oxychloride and N,N-diethylaniline are described.
9-Amino-6-chloropurin-8-ol monohydrate reacted with
phosphorus oxychloride and N, N-diethylaniline to yield
the phosphorus oxychloride adduct. Other purin-8-ols
were prepared and the production of analogs similar to
the previously mentioned adduct was attempted.
6-Chloropurin-8-ol and 6, 9-diaminopurin-8-ol hydrochloride
monohydrate...
A spectral investigation of the molecular vibration region of
the potassium sulfate crystal system was undertaken. This study was
initiated to establish the feasibility of using this crystal as a
host matrix for ammonium sulfate. Since these two systems are isomorphic
and have unit cells of nearly equal volume the...
The epoxide deoxygenation reaction is formally the reverse of theepoxidation reaction. Compared to epoxidation, which has reached its fullmaturity, epoxide deoxygenation has not been as intensively developed.Among the few deoxygenation reagents, a handful are catalytic in a metalcomplex, show high stereospecificity and operate under mild conditions. Acommon feature of all...
Oxylipins are a class of bioactive lipid metabolites derived from polyunsaturated fatty acids (PUFAs) via enzymatic and non-enzymatic pathways. In order to elucidate their overall biological effects, the knowledge of the entire oxylipin profile is needed as oxylipins can have similar or opposing effects in regard to inflammatory events. Their...
Rapamycin (5) was isolated in 1975 from the soil bacteria Streptomyces hygroscopicus and its structure was determined from spectroscopic techniques and an x-ray crystallographic analysis. Although it was initially found to exhibit antibiotic activity, it was subsequently shown to possess potent immunosuppressive activity as well.
Three approaches to the synthesis...
Several new solid-state inorganic borates have been prepared and
characterized. Single crystals of the simple orthoborate ScB0₃ were
grown and its structure was determined by single-crystal X-ray
methods. The new borates Li₃Sc(B0₃)₂, LaSc₃(B0₃)₄, NdSc₃(B0₃)₄,
SrNaB0₃, and Li4Ln4MB90₂₃ (Ln = Y, Er, and Gd; M = Al and Ga) were
identified...
This dissertation is separated into two parts according to the two major distinct research projects. In Part I, the full account of synthetic studies toward C10-functionalized lycopodium alkaloids is described. In Part II, the detailed discussion on the exploration of the Pummerer cyclization methodology and its application to the total...
The primary focus of this work is on examining structure-property relationships of interest for high-power nonlinear optical and laser crystals. An intuitive and simply illustrated method for assessing the nonlinear optical potential of structurally characterized noncentrosymmetric materials is introduced. This method is applied to materials including common quartz and tourmaline...
Due to the high cost of precursor materials, complex oxides of 4d and 5d transition metals are under-studied compared to their 3d counterparts. Recent studies have shown that oxides containing heavier transition metals can exhibit exotic electronic states due to presence of strong spin-orbit coupling. The goal of this dissertation...
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3 Tuning Ir Oxidation State in Ba2InIrO6 and BaLaInIrO6 via A- and B-site Substitutions
