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Articles 811 - 840 of 2077

Full-Text Articles in Physical Sciences and Mathematics

Integrated Geophysical Examination Of A Former Refinery Site, Carson City, Michigan, Kennedy Opiyo Mwanda Dec 2002

Integrated Geophysical Examination Of A Former Refinery Site, Carson City, Michigan, Kennedy Opiyo Mwanda

Masters Theses

Integrated geophysical surveys, including electromagnetic (EM-31), magnetic, dc resistivity, and ground penetrating radar (GPR) methods and soil borings were used to investigate part of a former refinery site in Carson City, Michigan, which has more than a 50-year history of hydrocarbon contamination.

Although not readily evident on the magnetic anomaly maps, the EM-31 conductivity map clearly revealed many sections of buried pipes of various lengths and orientations. Also evident on the EM maps are extensive near surface conductivity anomalies. Soil borings in zones of anomalous conductivities to the west suggest the presence of shallow clays with pooled hydrocarbons at depths …


Metal Ion Separation Mediated By Organized Molecular Assemblies, Hong Cao Aug 2002

Metal Ion Separation Mediated By Organized Molecular Assemblies, Hong Cao

Masters Theses

We have investigated the separation of Co(II), Ni(II), Cu(II) and Zn(II) by the ligands 8-hydroxyquinoline- 5-sulfonic acid and 7-iodo-8-hydroxy-quinoline- 5-sulfonic acid in the presence of the anionic surfactant sodium dodecyl sulfate (SDS) and the cationic surfactant octyltrimethylammonium bromide (OTAB) . Baseline separations have been achieved by HPLC employing an octadecylsilanized silica (ODS) column. The underlying mechanisms of separation have been determined.

The significant new results of our studies are: (1) separation is not possible without the presence of surfactants and hence organized assemblies; (2) separations can be achieved under submicellar concentrations; (3) the separations are not driven by micelles; and …


The Role Of Groundwater And Surface Water Interaction In The Development Of A 1,4-Dioxane Plume In Scio Township, Washtenaw County, Michigan, James W. Brode Jun 2002

The Role Of Groundwater And Surface Water Interaction In The Development Of A 1,4-Dioxane Plume In Scio Township, Washtenaw County, Michigan, James W. Brode

Masters Theses

The purpose of this study was to examine the hypothesis that groundwater and surface water interaction resulted in the development a 1,4-dioxane plume in a glacial aquifer in Scio Township, Washtenaw County, Michigan.

An industrial solvent, 1,4-dioxane, was detected in the groundwater in the area of study in 1986. This area, referred to in this investigation as the Western Plume, is one of several 1,4-dioxane plumes associated with the Pall/Gelman Sciences Inc. (P/GSI) site, an extensively investigated site of groundwater contamination.

1,4-Dioxane in the Western Plume area was initially believed to be the result of contaminated groundwater transported from a …


Multiple Isotopic Investigation Of Lake Sediments From Northern India, Alice Mwanda Jun 2002

Multiple Isotopic Investigation Of Lake Sediments From Northern India, Alice Mwanda

Masters Theses

Stable isotopes ratio of lake sediments can provide valuable environmental information. This possibility has been investigated using radiocarbon dated fossil lake sediments from the Himalayan region of Northern India. The chronology was established using Radiocarbon dating of both organic and inorganic fractions using (AMS). Inorganic ages are older than organic ages. Organic ages are expected to increase stratigraphically, however several anomalous old ages are found in the younger part of the sediments. Final chronology, determined using selected sensible ages identified two periods of sedimentation. The high sedimentation period is characterized by sedimentation rate of 0.8cm/yr and it fairly coincides with …


Determining Flow Type In A Carbonate Bedrock Aquifer, Presque Isle County, Michigan, Bonny Armstrong Apr 2002

Determining Flow Type In A Carbonate Bedrock Aquifer, Presque Isle County, Michigan, Bonny Armstrong

Masters Theses

Presque Isle County, Michigan, has a long history of ground water quality problems. Aquifer contamination is most likely the result of large fractures in the bedrock allowing surface water to rapidly reach ground water. The purpose of the study is to l) perform a geochemical investigation of ground water in the bedrock aquifer, 2) suggest the type of ground water flow system present in the study area and characterize the aquifer type, and 3) suggest how the flow system might affect the behavior and transport of contaminants.

Water samples were collected from sixteen wells in the Genshaw Formation, three wells …


Separation Of Enantiomers With Chiral Dendrimer, Jie Zhuang Apr 2002

Separation Of Enantiomers With Chiral Dendrimer, Jie Zhuang

Masters Theses

Chiral dendrimers with .unique ordered structures are especially attractive for the recognition of chiral molecules based on the three point contact model. We have successfully synthesized first generation chiral dendrimers containing L- and D- tryptophan methyl ester moieties and characterized them by NMR, IR, UV-Visible, MS, and optical activity. L-tryptophan methyl ester dendrimer was converted to its acid form in order to attach it to aminopropyl silica for the HPLC separation of enantiomers. The aminopropyl silica containing 1.52mmols/g of NH2 groups binds about 0.3mmols of dendrimer per gram and has about 0.4mmols of free NH2 groups per gram. …


Stratigraphic Analysis Of Diamicton Units In Southern Allegan County, Michigan, Shannon A. Wong Apr 2002

Stratigraphic Analysis Of Diamicton Units In Southern Allegan County, Michigan, Shannon A. Wong

Masters Theses

Two diamicton units from the southern Allegan County, Michigan lakeshore bluffs were identified and differentiated through clay mineralogy by analysis of 7 /10A peak-height ratios and the 2-80 mm crystalline fraction from pebble count results. t-Tests indicate the two units are significantly different. These two units are correlated with the Saugatuck and the Ganges tills of southwest Michigan based on similarities in stratigraphic position and lithologic description as described by Monaghan et al. (1986). Other diamicton samples were collected throughout southwest Michigan, near Moline, Otsego, Bloomingdale, Gobles, and Decatur. In correlating the Saugatuck and the Ganges tills to their inland …


Electrical Resistivity Tomography And Induced Polarization Techniques With Paired Vertical Resistivity Probes, Adrian Ezeagu Apr 2002

Electrical Resistivity Tomography And Induced Polarization Techniques With Paired Vertical Resistivity Probes, Adrian Ezeagu

Masters Theses

The aim of this research is to use electrical resistivity and induced polarization (IP) techniques to image in detail the vertical and lateral distribution of resistivity and chargeability in the subsurface region between two or more boreholes. The method involves installing electrodes mounted on PVC pipes in the boreholes. The distribution of resistivity and chargeability around the boreholes is then calculated. The large number of measurements taken is then inverted to produce tomographs or images showing subsurface distribution of resistivity and chargeability. Four cross-hole measurement arrays (pole-pole, dipole-pole dipole-dipole and pole-dipole) were employed in acquiring tomographic data. The tomographs produced …


A Comparison Of Vertical Velocity Profiles From The Balloon Borne Sounding System And The 915/50 Mhz Radar Wind Profiler/Radio Acoustic Sounding System To Parcel Theory At The Arm Sgp Site, Joshua R. Ravenscraft Jan 2002

A Comparison Of Vertical Velocity Profiles From The Balloon Borne Sounding System And The 915/50 Mhz Radar Wind Profiler/Radio Acoustic Sounding System To Parcel Theory At The Arm Sgp Site, Joshua R. Ravenscraft

Masters Theses

In this study we characterized vertical wind velocity profiles in the troposphere using the Atmospheric Radiation Measurement (ARM) equipment facility at the Southern Great Plains (SGP) site in Lamont OK established by the Department of Energy (DOE) and administered through Argonne National Laboratories (ANL). Using the Balloon Borne Radio Sonde (BBSS) system launched four times per day, we collected ambient temperature profiles and lapse rates from the period of June to September of

2001. Concurrently the Rass Radar Wind Profiler collected vertical wind speed data at 915 MHz continuously throughout this period. The BBSS data is visualized using a Skew-T …


A Web Content Management And Personalization Model Using One-To-One Strategy For Higher Educational Institutions, Yee Pong Ng Jan 2002

A Web Content Management And Personalization Model Using One-To-One Strategy For Higher Educational Institutions, Yee Pong Ng

Masters Theses

This research explored a Web content management and personalization model for higher educational institutions. Through a review of literature and data collected from users, it formulated a conceptual model for Web content management and personalization. The study used the Web site of School of Technology at Eastern Illinois University as a typical case from which to develop the model for higher educational institutions. Understanding the factors influencing user attitudes about the adoption of new Web technologies is extremely important. Such an understanding can help Web developers develop a theoretical framework for a Web model as well as identify its components. …


Stratigraphy And Diagenesis Of The Paleoproterozoic Bushy Park Zinc-Lead Deposit, South Africa, William Daniel Baugaard Jan 2002

Stratigraphy And Diagenesis Of The Paleoproterozoic Bushy Park Zinc-Lead Deposit, South Africa, William Daniel Baugaard

Masters Theses

“The Bushy Park zinc-lead deposit is located in the Northern Cape Province, South Africa. The sulfides are hosted by karst-related breccias that were formed in carbonate shelf deposits of the Neoarchean (2.55 Ga) Campbellrand Subgroup. These rocks are dolomitized completely and silicified partially but have not undergone major metamorphism and thus display remarkable preservation of depositional fabrics. The stratigraphic interval includes the Papkuil and Klippan Formations (> 210 m), a sequence of cyclic microbial laminates interbedded with domed and columnar stromatolites. The Klippan is distinguished from other formations b intense silicification and brecciation. These strata are overlain by the Kogelbeen …


Mechanical Response Of Nets Of Graphical Objects, Rakesh Kumar Bajaj Jan 2002

Mechanical Response Of Nets Of Graphical Objects, Rakesh Kumar Bajaj

Masters Theses

"This research produces networks of graphical objects that respond to human manipulation in a fashion that would be deemed physically reasonable. That is, a graphical network is given a mechanics-like behavior in the presence of the human interaction. In this approach, nonlinear models replace commonly used linear models to mimic physical reality better. Software solutions are provided via a class library useful for such interactive visual modeling"--Abstract, page iii.


Glass Transition Behavior Of Thin Poly(Methyl Methacrylate) Films On Silica, Moses T. Kabomo Jan 2002

Glass Transition Behavior Of Thin Poly(Methyl Methacrylate) Films On Silica, Moses T. Kabomo

Masters Theses

"Modulated Differential Scanning Calorimetry (MDSC) was used to study the glass transition behavior of poly(methyl methacrylate) (PMMA) adsorbed onto silica substrates from toluene. Untreated fumed amorphous silica and silica treated with hexamethyldisilazane were used for the adsorption to probe the effect of polymer- substrate interactions. To test the effect of molecular weight on the Tg of adsorbed polymers, low polydispersity PMMA samples of varying molecular weights were used. The results revealed a broadening of the glass transition towards high temperatures. The observed increase in the glass transition breadth varied with adsorbed amount and the type of silica used for …


Characterization Of Organo-Tin And Organo-Mercury Compounds With Electrospray Mass Spectrometry, Kan Zhu Dec 2001

Characterization Of Organo-Tin And Organo-Mercury Compounds With Electrospray Mass Spectrometry, Kan Zhu

Masters Theses

Metal-containing compounds are often found as pollutants in the environment. Obtaining speciation information about these compounds is important to understanding toxieity and bioaccumulation. Electrospray Mass Spectrometry (ESMS) is a technique that has the potential to provide rapid and direct speciation information of solution phase metal compounds. The ionization behavior of chemical species is related to their electron affinities. The higher the electron affinity, the easier it will be reduced during the ionization process. Additionally, solvent with different polarity and surface tension will also affect the ionization and reduction products. Organo-tin compounds with more alkyl groups will be ionized more efficiently, …


Pan, Ppn And Mpan Measurements And The Quantitative Relationship Of Pan And Mpan In Biogenic Hydrocarbon Conditions, Chen Wangchun Dec 2001

Pan, Ppn And Mpan Measurements And The Quantitative Relationship Of Pan And Mpan In Biogenic Hydrocarbon Conditions, Chen Wangchun

Masters Theses

Simultaneous measurements of PAN, PPN and MPAN were made during the SOS 1999 Nashville campaign at Dickson site. The PANs data at this site were rich and complex. PAN and MP AN showed obvious diurnal change but PPN did not during this period. PAN and ozone have a clear positive relationship. Due to the special location of the site, winds from different directions bring anthropogenic hydrocarbons (AHCs) or biogenic hydrocarbons (BHCs) to the site. The data showed that the influence of AHCs and BHCs on PANs compounds varied on different days. Average values of PAN/PPN and PAN/MPAN from MLR may …


A Qualitative Investigation Of The Polymerization Process In The Ihss Humic Substances Extraction Procedure Using Model Phenolic Compounds, Roger J. Germay Aug 2001

A Qualitative Investigation Of The Polymerization Process In The Ihss Humic Substances Extraction Procedure Using Model Phenolic Compounds, Roger J. Germay

Masters Theses

Achard (1786) extracted peat with alkali and reported obtaining dark compounds now called humic substances. These are complex, high molecular weight, polyphenolic compounds naturally occurring in soil, in fresh-water and in marine environments. They are biodegradation products of plant materials.

The International Humic Substances Society (IHSS) adapted Achard's method to separate humic substances into three fractions: (1) humic acids (HA), soluble only at high pH; (2) fulvic acids (FA), water-soluble at any pH; and (3) humin, insoluble at any pH. The IHSS method involves contact of soil with 0.1N.NaOH solution, followed by acidification with HCl.

In this study, 0.01 N. …


Alkyl Nitrates In Dickson During The Sos 1999 Field Campaign, Mei Ma Aug 2001

Alkyl Nitrates In Dickson During The Sos 1999 Field Campaign, Mei Ma

Masters Theses

Measurements of alkyl nitrates were performed during the Southern Oxidants Study (SOS) 1999 Summer Field Campaign in Dickson, TN from June 10 to July 15, 1999. The developed GC-ECD method was tested and used successfully. Nine alkyl nitrates were measured and six alkyl nitrates were quantified. The measured alkyl nitrates expect methyl nitrate showed higher mixing ratios under northeasterly and southeasterly wind, which brought anthropogenic sources to the measurement site, and lower mixing ratios when wind came from northwest and southwest, which brought NOx and clean air, respectively. The contribution of the measured alkyl nitrates to the total oxidized nitrogen …


In Situ Biosurfactant Production At Carson City Park, Michigan, Andrew J. Hudak Jun 2001

In Situ Biosurfactant Production At Carson City Park, Michigan, Andrew J. Hudak

Masters Theses

Crude oil refining operations conducted by the Crystal Refining Company in Carson City, Michigan have led to the contamination of the soil and groundwater at Carson City Park with petroleum hydrocarbons. In situ biosurfactant production, occurring as a result of the biodegradation activities of hydrocarbon degrading microorganisms, was investigated.

Background hydrogeological and biogeochemical data were collected from the groundwater from thirteen monitoring wells at Carson City Park. Further analysis included the identification of biosurfactant producing microorganisms and biosurfactants present in the soil and groundwater.

Results showed that Pseudomonas aeruginosa was producing both monorhamnolipids and dirhamnolipids (glycolipid biosurfactants) in the contaminated …


Surface Modification Of Diamond And Determination Of Kinetics And Mechanism Of Modification Reactions, Humera Farooq Jun 2001

Surface Modification Of Diamond And Determination Of Kinetics And Mechanism Of Modification Reactions, Humera Farooq

Masters Theses

A series of photochemically modified diamond surfaces were prepared. Surface functional groups added included, chlorine, bromine, methoxy, amine, methylamine, dimethylarnine and trimethylammonium chloride. Photochemically chlorinated and brominated diamond surfaces were used as synthetic intermediates. The modified diamond surfaces were characterized by Diffuse Reflectance Infrared Spectroscopy (DRIFT) and X-ray Photoelectron Spectroscopy (XPS).

The study was mainly focused on understanding the kinetic processes and reaction mechanism of modified surfaces. The observed rate constants for surface hydrogen loss and HCl (g) evolution were found to be identical. Similar rate constants were observed for amine substitution and consumption of ammonia.

The study of action …


Apoptosis Following Peripheral Sensory Deafferentation In The Olfactory Blub Of Adult Zebrafish, Danio Rerio, Akiko M. Vankirk Jun 2001

Apoptosis Following Peripheral Sensory Deafferentation In The Olfactory Blub Of Adult Zebrafish, Danio Rerio, Akiko M. Vankirk

Masters Theses

Removal of the olfactory organ in the adult zebrafish results in a significant decrease in volume of the ipsilateral olfactory bulb. Our lab has been investigating the potential role of apoptosis in this phenomenon. My hypothesis is that cells in the adult olfactory bulb normally undergo minimal apoptosis and that apoptosis will increase when sensory stimulation is removed. The TUNEL method allowed detection of cells undergoing DNA-fragmentation, which indicates an apoptotic response. Double-label immunohistochemistry was used to mark which apoptotic cells are neurons by using antibody to Hu, a neuron specific protein. Triple-labeling with bis-benzirnide confirmed the apoptotic nature of …


The Geochemistry Of A Leaf Composting Leachate Plume, Asylum Lake, Kalamazoo, Michigan, Eric G. Steeves Jun 2001

The Geochemistry Of A Leaf Composting Leachate Plume, Asylum Lake, Kalamazoo, Michigan, Eric G. Steeves

Masters Theses

Since the implementation of legislation that bans yard waste from landfills, there has been a need to characterize the impact that large scale composting has on groundwater quality. Allen (1993) and Weaver (1995) have attempted to characterize a leaf composting leachate plume located at the WMU-Asylum Lake Well Field #2 in Kalamazoo, Michigan. Allen was not able to base any conclusions on geochemical results and Weaver delineated the plume using fewer monitoring wells than are now available.

The data from twenty-one monitoring wells indicates that local groundwater is being impacted by the large-scale composting operation. The plume is characterized by …


An Investigation Of Friedel-Crafts Alkylation Reactions In Super- And Subcritical Carbon Dioxide And Under Solventless Reaction Conditions, Kan Nie Apr 2001

An Investigation Of Friedel-Crafts Alkylation Reactions In Super- And Subcritical Carbon Dioxide And Under Solventless Reaction Conditions, Kan Nie

Masters Theses

This study investigates the Friedel-Crafts alkylation reaction of triphenylmethanol with methoxybenzene (anisole) in supercritical and subcritical carbon dioxide, and under solventless reaction conditions. The reaction was initiated using trifluoroacetic acid to produce triphenylmethylcarbocation as the reaction intermediate. Isolated product yields of the Friedel-Crafts product, p-methoxytetraphenylmethane, are reported. The possibility of using the above reaction as an alternative synthesis in an undergraduate organic laboratory to teach some of the tenets of green chemistry is also presented. Additionally, we have investigated the use of benzhydrol, 9-hydroxyxanthene and 9-phenylxanthen-9- ol as potential carbocation sources for supercritical carbon dioxide synthesis and we report those …


Constraining The Crystallization And Post-Crystallization History Of The Wallamatogus Pluton, Maine, Using Compositional Data From Garnet, Biotite And Muscovite, Joy Kathleen Drake Jan 2001

Constraining The Crystallization And Post-Crystallization History Of The Wallamatogus Pluton, Maine, Using Compositional Data From Garnet, Biotite And Muscovite, Joy Kathleen Drake

Masters Theses

"The Wallamatogus Pluton, Maine, exhibits systematic variation in grain size, mineralogy, and phenocryst abundance (alkali-feldspar) from the margin to the center of the pluton. Three facies are recognized: 1) outermost, seriate, coarse-grained (Owe), 2) porphyritic medium- to fine-grained (Dwp ), 3) innermost, fine-grained equigranular (Dwf). These facies are concentrically arranged and their contacts are gradational. Muscovite and biotite occur in all facies; the outer two facies contain garnet, and tourmaline. Muscovite and biotite grains within micaceous enclaves compositionally overlap primary muscovite, suggesting that they are early-crystallized accumulations. Muscovite in multiphase clusters and secondary muscovite compositionally overlap, suggesting formation during post-crystallization …


Computational Studies Of Constant Bond Dissociation Enthalpy Ratios And Novel Structures For [H3, B, C, F]+, Le Li Jan 2001

Computational Studies Of Constant Bond Dissociation Enthalpy Ratios And Novel Structures For [H3, B, C, F]+, Le Li

Masters Theses

This thesis describes two separate computational chemistry projects. The first project is a study of constant bond dissociation enthalpy ratios, and the second project is a study of the rearrangement and fragmentation processes on the singlet potential energy surface of the [H3, B, C, F]+ system.

G2 and G2(MP2) enthalpies have been calculated for isoelectronic AB2 systems with singlet-linear, singlet-nonlinear, triplet-linear, and triplet-nonlinear electronic states and geometries, and for isoelectronic AB systems with singlet and triplet electronic states. For these systems, A = B-, Al-, Ga-, C, Si, Ge, N …


Pentacarbonyl Derivatives Of Polydentate Phosphines, Yi Zang Jan 2001

Pentacarbonyl Derivatives Of Polydentate Phosphines, Yi Zang

Masters Theses

Four phosphines (Ph2P)2C=CHPPh2, (p-tol)2PCH2P(p-tol)2, (o-tol)2PCH2P(o-tol)2, Ph2PCH2P(p-tol)2 and their pentacarbonyltungsten complexes have been prepared and studied as part of a continuous investigation of polydentate phosphines that are coordinated as monodentate ligands. The ligand, (Ph2P)2C=CHPPh2, was prepared by base-catalyzed addition of Ph2PH to Ph2PC=CPPh2. Reaction of this ligand with (OC)5WNH2Ph led to formation …


Computational Studies Of Regularities In Bond Dissociation Enthalpies And Interactions Of Acetylthiocholine With Solvent Molecules, Wencui Zheng Jan 2001

Computational Studies Of Regularities In Bond Dissociation Enthalpies And Interactions Of Acetylthiocholine With Solvent Molecules, Wencui Zheng

Masters Theses

This thesis reports the results of two different research projects. One project is an evaluation of the feasibility of applying constant bond dissociation enthalpy ratios to neutral molecules for which one atom is from group 13 or group 17 and the other atom is from group 16. The other project attempts to validate the proposal that the aromatic residues lining the acetylcholinesterase (AChE) gorge will induce entry of acetylthiocholine (ATCh) into the gorge in a manner similar to that of the neural transmitter acetylcholine.

A total of thirty AB2 and AB molecules have been examined, where A = B, …


The Reactivity Of Boron And Aluminum Compounds With Silica Gel Surfaces, Jeannine M. Christensen Jan 2001

The Reactivity Of Boron And Aluminum Compounds With Silica Gel Surfaces, Jeannine M. Christensen

Masters Theses

The unmodified silica gel surface contains isolated silanols, vicinal silanols, and siloxane species. Silica gels can be thermally and/or chemically treated to obtain a desired surface. Hexamethyldisilazane (HMDS) was used to chemically modify the silica gel to obtain a surface that contains vicinal silanol groups and siloxane species. The silica gel was thermally treated at 600°C to create a surface that contains isolated silanols and siloxane species. Four types of silica gels (unmodified, 600°C, HMDS and 600°C/HMDS) were reacted with three boron compounds. The boron compounds used were boron trichloride (BCl3), triethyl borane (B(CH2CH3) …


Adaptive Web Sites By Web Usage Mining, Mario Rodney Creado Jan 2001

Adaptive Web Sites By Web Usage Mining, Mario Rodney Creado

Masters Theses

The World Wide Web has become a very popular marketing medium during the recent years. Many businesses use it extensively to publicize their products. Initially it began with static web sites. However as web sites got bigger and better, their maintenance became problematic. Just as business strategies change, so also will the orgainization of their web sites change. Hence the need of the hour is an adaptive web site (i.e. a web site that can organize itself based upon its usage). For this purpose, web usage mining techniques are used. The characteristics of the user's activity on the web site …


Linkage Isomers Of Tungsten Carbonyl Complexes Of Ph₂Pch₂Pphch₂Pph₂, Chaminda P. Gamage Jan 2001

Linkage Isomers Of Tungsten Carbonyl Complexes Of Ph₂Pch₂Pphch₂Pph₂, Chaminda P. Gamage

Masters Theses

The linkage isomers (CO)5W[η1-PPh2CH2PPhCH2PPh2], 1, and (CO)5 W[η1-PPh(CH2PPh2)2], 2, have been synthesized from the reaction of (OC)5W(NH2Ph) and Ph2PCH2PPhCH2PPh2. In addition, linkage isomers (CO)5W[μ-PPh2CH2PPhCH2PPh2]-W(CO)5, 3, and (CO)5W{μ-PPh2CH2PPh[W(CO)5] CH2PPh2}, 4, have been prepared. Attempts to obtain (OC)5WPPh2CH …


A Ring-Closing Strategy For The Synthesis Of Β,Γ-Unsaturated Δ-Lactones, Erbing Hua Jan 2001

A Ring-Closing Strategy For The Synthesis Of Β,Γ-Unsaturated Δ-Lactones, Erbing Hua

Masters Theses

Spiro β,γ-unsaturated δ-lactones and fused β,γ-unsaturated δ-lactones are integral to a large number of naturally occurring compounds exhibiting a diverse range of biological activity. A new synthetic route to β,γ-unsaturated δ-lactones, consisting of a three-step sequence, has been investigated for the synthesis of these kinds of pharmacological intermediates. Ring closure of a β-hydroxy acid by dehydration, providing a 4-vinyl substituted β-lactone, and its ring expansion/rearrangement are the two key steps in this protocol. The results have proved that this new method is efficient and quite expeditious. One spiro and four fused β,γ-unsaturated δ-lactones were synthesized through this protocol albeit in …