An approach to the generation of polyketides was investigated,
which involved ozonolysis of 6, 7 cyclopenteno -1> 4, 5, 8 -tetrahydromethoxy-
3-methylnaphthalene (26), to produce what is believed to be
polyketide 27. Compound 26 was formed by the following sequence:
Die ls -Alder addition of 1, 2 -dim.ethylenecyclopentane and 2...
A formal total synthesis of the macrolactone pyrolizidine alkaloid (-)-integerrimine (2), from R-(+)-citronellal (93) is described. Aldehyde 93 was converted to exo methylene derivative 94 which was reduced to allylic alcohol 95. The epoxides 96 and 98, obtained in a ratio of 3:1 respectively by Sharp less epoxidation of 95...
Verrucarol is the sesquiterpene portion of a number of macrocyclic di- and triesters of potential medicinal importance. In this study, a novel approach to the synthesis of this fungal metabolite is presented. An A-B-C route was investigated in which C-3 and C-4 of the C-ring were emplaced using a [2+2]...
The mycosporins, formerly called P310's are secondary metabolites
of fungi closely associated with fungal reproductive processes that
require light. The structurally related iminomycosporins are found in
marine plants and animals and may also have functions related to
light. In this study, approaches toward the asymmetric synthesis of
the mycosporins are...
The variegated aqueous chemistries of metal cations are applied to the design and synthesis of non-toxic solution precursors suitable for additive printing of large-area oxide electronics. Polycondensation behaviors of aqueous Al+3 and PO4 +3 are manipulated in the deposition of atomically smooth amorphous aluminum oxide phosphate (AlPO) dielectric films. AlPO...
Carboxylic acids have played an important role in the field of actinide (An) and lanthanide (Ln) separations and the reprocessing of irradiated nuclear fuel. Recent bench-scale experiments have demonstrated that 3-carboxy-3-hydroxypentanedioic acid (citric acid) is a promising aqueous complexant that can effectively aid in the separation of transition metals from...
Phosphate and peroxide stabilize new oxo-hydroxo niobium clusters in water at low pH. The clusters open a new chapter in aqueous niobium chemistry under acidic conditions. The clusters also produce atomically smooth, amorphous niobium oxide phosphate (NbPOx) thin films. Reaction pathways from cluster solutions to amorphous niobium oxide phosphate solids...
The work described herein details the synthesis and application of
biphenyls that probe the effects of hydrogen, Cl / Br, and methyl substituents
on the aryl ring of the terminal acetylenic carbon. From this work, we
successfully developed the rapid synthesis of phenyl acetylenes in 3-4 steps
from inexpensive commercially...
The rearrangement of a homoallyl cation to a cyclopropylcarbinyl cation is thought to play a role in the biogenesis of a variety of cyclopropane-containing natural products,¹ a hypothesis which has previously led to the design of successful biomimetic syntheses of several natural products.² The strategy underlying this approach to cyclopropane...
The atmospheric trace element abundances associated with slash
burning have been measured by instrumental neutron activation analysis
(INAA). On site ground level samples were collected during the slash
burning season using high volume samplers and a cascade impactor. In
addition to the air samples, soil, wood and ashed wood samples...
The atmospheric trace element abundances associated with
several major sources of air pollution in Western Oregon, such as the
paper industry, the metallurgical processing industry, the plywood
industry and agricultural field burning have been measured by instrumental
neutron activation analysis (INAA). Air samples were collected
directly from industrial stacks and...
Ambient high-volume (hi-vol) air samples were collected between March 15th and May 30th 2002, at Cheeka Peak Observatory (CPO), located on the tip of the Olympic Peninsula, Washington State. This sampling campaign was in conjunction with the 2002 Inter-Continental Transport and Chemical Transformation (ITCT 2K2) Campaign and the Photochemical Ozone...
The relative rates of hydrogen atom abstraction from a series of 13 homoaryl
and heteroarylmethanes by the nucleophilic undecyl radical, thermally generated
from lauroyl peroxide, were determined at 70 °C. A reactivity range of 15 was
obtained. Substantial differences in reactivity among isomers were found. The
relative reactivities of the...
7,7'-Dihydroxy-8,8'-biquinolyl (azaBINOL) was prepared from 7-hydroxyquinoline via N,N-dimethyl O-quinol-7-yl carbamate by directed ortho-metallation followed by FeCl₃-mediated oxidative coupling of the 8-lithioquinoline intermediate. Saponification of the resulting dicarbamate provided crystalline (±)-azaBINOL in 56% overall yield. 6,6'-Bis(dimethylaminocarbonyl)-7,7'-dihydroxy-8,8´-biquinolyl was prepared from the same dicarbamate by a double anionic-Fries rearrangement in 43% yield. 7,7'-Bis(diethylamino-carbonyloxy)-6,6'-diiodo-8,8´-biquinolyl...
An automatic, continuous analyzer has been developed which
is suitable for estimating the level of spent sulfite liquors (SSL) in
laboratory samples. The analyzer makes use of a version of the
Pearl-Benson, or nitroso method, and, in its present form, is
useful for samples whose actual SSL solids concentrations are...
The nuclear reaction ¹⁰⁰Mo(¹²⁴Sn,xn)[superscript 224-x]U has been carried out at E[subscript cot] of 578 MeV and 634 MeV using the facilities and equipment at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory (ORNL) in order to initiate the search for the inverse fission of uranium. Reference...
Natural products from plants, bacteria, and fungi play an important role in society. Over the last 35 years, natural products and their derivatives have inspired over 60% of all FDA approved small-molecule drugs, and are among the top prescribed therapeutics.1-2 Fleming’s discovery of the fungal antibiotic penicillin started the “Golden...
The oxidation of sorbitol by soluble extracts of A. suboxydans proceeds by two pathways depending upon which pyridine nucleotide is present. In the presence of TPN, sorbose is formed. In the presence of DPN fructose is
produced. Both products of the oxidation of sorbitol have been identified by paper chromatography,...
Fungi have long been used for discovery of new chemical scaffolds. In the clinical setting, the fungal natural products penicillin, statins, and cyclosporine have revolutionized medicine to treat diseases and infections. In the environment, fungal natural products have been used as herbicides, fungicides, and insecticides to protect crops, livestock, and...
Feeding of [3-¹³C, 2-¹⁵N]arginine, 38a, unequivocally established that the β-
arginine moiety of blasticidin S, 1, was formed from α-arginine by an intramolecular
migration of the α-amino group to the β- position. Further feedings using chirally
deuteriated arginines 38e and 38f revealed that the aminomutase process occurred with
inversion of...
Ultrafast spectroscopy has recently gained momentum as a powerful, noninvasive characterization toolset capable of studying a diverse array of samples with applications in chemistry, physics, biology, engineering, and more. Two popular ultrafast spectroscopic techniques include femtosecond transient absorption (fs-TA) and femtosecond stimulated Raman spectroscopy (FSRS). The latter of these techniques...
An intramolecular variant of the modified-Julia olefination was demonstrated by the synthesis of α,β-unsaturated lactones in a mild and (Z)-selective fashion. The lynchpin reagent (benzothiazol-2-sulfonyl) acetic acid was synthesized in a straightforward fashion in 86% overall yield from commercially available 2-mercaptobenzothiazole via conversion to ethyl (benzothiazol-2-ylthio)acetate by base mediated alkylation...
Ultrafast spectroscopy can exploit the structure-function relationship of chemical- and biological-based systems. More specifically, femtosecond stimulated Raman spectroscopy (FSRS) provides ground- and excited-state vibrational information with simultaneously high spectral (spatial) and temporal resolutions. The electronic counterpart, femtosecond transient absorption (fs-TA), complements FSRS data analysis as part of a comprehensive approach...
The tosylhydrazones of exo-3-deuteriocamphor and 2- deuterio-2,4-dimethy1-3-pentanone were treated with Nbromosuccinimide (NBS) and pyruvic acid to regenerate the parent ketones. The ketones from the pyruvic acid cleavage show a significant loss of deuterium. The ketones from the NBS cleavage show no loss of deuterium, indicating that stereochemical integrity at. C[subscript...
The tosylhydrazones of 2-heptanone, 4,4-dimethy1-2-
heptanone, 6-heptyn-2-one and 4,4-dimethy1-6-heptyn-2-
one were synthesized and decomposed under a variety of
reaction conditions: dry lithium and sodium salt pyrolyses,
sodium methoxide thermolyses in diglyme and photolyses of
the lithium salt in tetrahydrofuran. The saturated analogues
2-heptanone tosylhydrazone and its 4,4-dimethyl
isomer afforded the...
There has been a tremendous growth in interest in carbon nanodots (C-dots) in the past several years. As a nascent nanomaterial, C-dots have shown great promise in applications that benefit from their superior water dispersibility, low toxicity, non-blinking fluorescent output, chemical and biological compatibility, ease of functionalization and resistance to...
Many D2d-symmetric 2,2',6,6'-tetrasubstituted biphenyls are
readily prepared via net oxidative dimerization of appropriate
1,3-disubstituted benzenes. Conversion of such proprochiral
compounds to useful C2-symmetric chiral biphenyls requires
formal replacement of two substituents on opposing aryl ring
units with alternate groups. This under exploited
desymmetrization tactic has been demonstrated for the
generation...
The reaction of cyclodeca-1,215triene with mercuric salts
gave only rearranged hydrocarbon, tricyclo[4.4.0.0²'⁴]deca-5ene
in acetic acid. Other catalysts [Rh(CO)₂C1]₂ and AgC10₄ gave
the same rearranged hydrocarbon. The isomerization is proposed
to proceed through a "metalcomplexed" carbenoid intermediate.
The reaction of bicyclo[7.1.0 ]deca-213diene gave
oxymercurated products.
In this dissertation, I describe the experimental investigation of catching ions in superfluid helium droplets. The ultimate goal of our project is to build a coherent electron diffraction apparatus for atomic structure determination from oriented single macromolecules. This involves generating protein ions from electrospray ionization (ESI) and doping them in...