A mechanism for filiform corrosion of aluminum is proposed
based on experimental evidence and the known aqueous chemistry of
the trivalent aluminum ion. Experimental methods utilized include
autoradiographs with Cl³⁶; pH paper determination of the filiform
head pH; activator concentration and activation period as they affect
filiform growth.
The pH...
Enantioselective epoxidation of crotyl alcohol, followed
by a cuprate mediated methylation, gave a 1:1 mixture of
(2S) -3- methyl -1,2- butanediol and (2R,3S)-2-methy1-1,3-
butanediol. The latter was separated as its 2,4,6-trimethylbenzenesulfonate
derivative and converted via the
iodide to the corresponding phosphonium salt. The separated
butanediol derivatives were independently transformed
to...
Thermal analysis was used to investigate the following seven
systems: H₂S-B₂F₄, SOF₂-B₂F₄, COC1₂-B₂F₄, SF₄-B₂F₄, Xe-BF₃, NF₃-BF₃, and NF₃-BC1₃. In two of the seven systems
compound formation was observed.
In the system, H₂S-B₂F₄ the compounds H₂S[superscript .]B₂F₄ and
2H₂S[superscript .]B₂F₄ are formed. The compound H₂S[superscript .]B₂F₄ has a melting
point of...
The retro-ene reaction of 2-vinylcyclohexanols occurs readily
in the vapor phase at 400-450° producing unsaturated carbonyl
compounds in good yields. The starting- materials were prepared in
general by the carbenoid addition reaction of ethyl diazoacetate,
appropriately substituted cyclohexene, and copper catalyst to
produce bicyclic esters which were reduced to the...
The production of C¹⁴O₂ metabolized from glucose labeled in
specific carbon atoms by homogenates of chick embryonic and adult
heart was compared by the radiorespirometric technique. Homogenates
of early (two to five days of incubation) embryo hearts were
found to utilize the phosphogluconate pathway of glucose catabolism
to a greater...
The spin-orbit states of both the ground and several
charge-transfer-excited electronic configurations of
gaseous MnX₂, CoX₂, NiX₂, and CuX₂ are derived. Only one-electron
transitions from the ground electronic state are
considered. The molecules are treated as linear in both
the ground and excited states. In each case, the spin-orbit
states...
Investigations of plasma production by a pulsed dye laser
microprobe were made. Comparisons between a Q- switched and a
pulsed dye laser system were made on the intensity of the continuum
produced by atmospheric breakdown. The dye laser system was
foundtominimize the production of the continuum which in turn
allowed...
Studies towards the total synthesis of (−)-kendomycin (1), a bacterial metabolite with
a unique molecular architecture and pronounced biological activity, are described. These
studies resulted in the synthesis of advanced intermediate 208, containing all of the
carbon atoms of 1.
A Dötz annulation between alkyne 122 and novel chromium carbenoid...
While properties are extremely important from an application point of view, it is crucial to have a detailed understanding of the underlying structural influence. Once a concrete correlation between the structure and the observed property is established, rational design of novel materials with optimized properties can be realized. These optimized...
A critical study of the cold vapor atomic absorption and fluorescence instrumentation for the analysis of mercury is described. Some of the important modifications involve the reduction vessel, absorption cell, fluorescence cell, and radiation source. The new modified systems have much greater calibration sensitivities and lower detection limits than those...
Fusion reactions with radioactive neutron-rich projectiles have been the subject of much recent theoretical and experimental interest. Predictions of enhancement of the cross section due to the use of a neutron-rich projectile may have implications for synthesis of heavy nuclei. In this work, the fusion-fission excitation functions were measured for...
An automated instrument based on a single-board microcomputer
was developed for use in voltammetric analyses. Operator input of
numerous experiment parameters allows any type of voltammetric
analysis to be implemented and multiple scans to be run unattended.
A three operational amplifier potentiostat is used to control
the cell voltage and...
Studies were carried out to determine the absolute stereochemistry of
botryococcene (1). The natural product was degraded to two sets of 'y- and 8-
valerolactones. All enantiomeric variations of these lactones were synthesized in
optically pure form starting from (S)- and (R)-methyloxiranes. 1H NMR correlation of
natural and synthetic materials...
Dysfunction of mitochondria has been linked to aging and the pathogenesis of many degenerative diseases. Aside from their primary function in energy production, mitochondria are considered as a major source and target of reactive oxygen and nitrogen species (ROS/RNS) in cells as well. The mitochondrial thiol proteome is a subset...
Part 1
The concentration of seventeen elements in two species of fungus
which cause wheat bunt disease, Tilletia caries (DC.)Tul. (TS) and
Tilletia controversa Kiihn (DS), were determined by instrumental neutron
activation analysis in 37 TS spore samples, and 31 DS spore samples.
Aluminum was chosen as a soil contamination...
The oxide/electrolyte solution interface has been studied experimentally by two methods, and a mathematical model for the interface has been developed. The change in interfacial potential with solution composition was determined through the capacitance of electrolyte/oxide/semiconductor (EOS) structures and the charge through potentiometric titrations of colloidal oxide suspensions. The differential...
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...
Biochemical studies of phenylmercuric acetate (PMA) and
mercuric acetate toxicity in rats carried out during this investigation
were (1) the metabolism of ²⁰³Hg(Ac)₂ and ²⁰³Hg-PMA within kidney and liver tissues following oral
ingestion,
(2) the effect on some
soluble enzyme activities and determinations of ²⁰³Hg binding in the
enzyme fractions,...
Bicyclo [6.1.0] non-4-ene was prepared by two routes; (1) reaction
of cis-cis-1, 5-cycloöctadiene with methylene iodide and zinc-copper
couple, (2) sodium-methanol reduction of 9, 9-dibromobicyclo-[6.1.0] non-4-ene. The bicyclononene was characterized by its infrared
spectrum, nuclear magnetic resonance spectrum and common
physical properties. The olefin was hydrogenated to bicyclo [6.1.0] -...
Fungi have long been a prolific source of clinically approved drugs. The antibiotic penicillin, the cholesterol lowering statins, and the immunosuppressant cyclosporine have changed the treatment of human diseases in the last century. Recently, genome analysis of filamentous fungi has revealed that the biosynthetic potential for natural product expression is...
Dihalocarbenes have been generated mainly by thermal decomposition
of sodium trihaloacetate and phenyl (trihalomethyl)mercury,
and give gem-dihalocyclopropyl adducts with various steroid olefins.
A new procedure involving the use of sealed tubes makes possible the
addition of dihalocarbenes to sterically hindered olefins. In this manner,
7-cholestenyl benzoate when treated with PhHgCC1₃...
Cyclopropylcyclobutene was prepared via the intermediate
dicyclopropylcarbinyl carbene which was generated by the thermal
decomposition of the sodium salt of dicyclopropylketone p-toluenesulfonylhydrazone.
The successive thermal isomerization of cyclopropylcyclobutene
to 2-cyclopropyl-1, 3-butadiene and to vinylcyclopentene
was studied. Kinetic data were obtained for the cyclopropylcyclobutene
to 2-cyclopropyl-1, 3-butadiene isomerization in the gas...
Levels of activity of glucose-6-phosphate- , 6-phosphogluconate- , and isocitric- dehydrogenase were measured in the
soluble and particulate fractions of heart, brain and liver at
several ages throughout the development of the chick embryo.
Compared to isocitric dehydrogenase, levels of glucosesphosphate-
, and 6-phosphogluconate- dehydrogenase are generally
low. This suggests...
Thermal decomposition of several di-p-toluenesulfonylhydrazones
was studied. It was found that the carbene decomposition
of tetramethyl-1,3-cyclobutanedione, di-p-toluenesulfonylhydrazone
gave two products resulting from
rearrangement. One was identified as 2,5-dimethyl-1,3,4-hexatriene. A tentative structure for the second was
proposed. During the course of the study, a more convenient
procedure for thermal decompositions was...
Examination of a proposed reaction scheme to prepare bicyclo-(2.2.0)hexan-1-ol produced the first known condensation of an
enamine with its carbonyl precursor. Hydrolysis of the resulting
dienamine gave an unusual conjugated cyclobutenone in which the
double bond is exocyclic. Characterization and reactions of the
cyclobutenone were successfully carried out.
New syntheses for 2-bicyclo(3.3.1)nonanone and 7-bicyclo-(3.3.1)nonen-2-one were developed. The saturated ketone was prepared
from phenol and acrylonitrile via a novel intramolecular
S[subscript N]2 cyclization process. A Friedel-Crafts cyclization of 3-(3-cyclohexenyl)propanoyl chloride permitted synthesis of the unsaturated
ketone from 4-cyclohexene carboxaldehyde. The formation of
the bicyclo(3.3.1)nonane rather than a bicyclo(3.2.2)nonane skeleton...
The 3-cyclohexenyl carbinyl carbene species was formed by the
thermal decomposition of the p-toluenesulfonylhydrazone sodium
salt and by oxidation of the hydrazone. Several oxidizing agents
were studied. The products were investigated under aprotic and
protic conditions and at various temperatures. The diazocompound
was formed as an intermediate and found to...