Some of the material in is restricted to members of the community. By logging in, you may be able to gain additional access to certain collections or items. If you have questions about access or logging in, please use the form on the Contact Page.
Some of the material in is restricted to members of the community. By logging in, you may be able to gain additional access to certain collections or items. If you have questions about access or logging in, please use the form on the Contact Page.
Spectroscopy and dynamics of reactive species in solution: Picosecond investigations of diaryliodonium salts and derivatives of 9-fluorene
Description:
Picosecond absorption spectroscopy permitted direct detection of several new reactive intermediates in bond dissociation reactions. Our study of 9-fluorenol and related substituted fluorenes led to a spectral assignment for the 9-fluorenyl cation, HFl$\sp+$, which exhibits a $\lambda\sb{\rm max}$ at 515 nm and has a lifetime of $<$20 ps in 9:1 H$\sb2$O/CH$\sb3$OH. In... Picosecond-pulsed irradiation of 9-diazofluorene in hexanes, cyclohexane, CH$\sb2$Cl$\sb2$, and CH$\sb3$CN permitted the observation of a precursor of the ground-state triplet carbene, 9-fluorenylidene ($\sp3$Fl:). The precursor absorbs... The photochemistry of diaryliodonium salts was found to be highly dependent on the identity of the counterion: diphenyliodonium salts with complex counterions such as BF$\sb4\sp-$ or PF$\sb6\sp-$ decompose in CH$\sb3$CN or CH$\sb2$Cl$... The unsymmetrical p-anisylphenyliodonium salts exhibit similar behavior; however, the iodoanisole/chlorine-atom complex is unstable, and undergoes back-electron transfer to give the iodoanisole cation radical and chloride with a rate k =...
The aim of this work is to develop a deeper understanding of the nuances involved in designing and optimizing the performance of gas/liquid plasma reactors for chemical synthesis. The design of such reactors requires integrating...
AN INVESTIGATION OF THE MECHANISM OF THE PHOTOCHEMISTRY OF 1,1'-BICYCLOHEXENYL (DIENES, ALKENES)
Description:
The mechanism of the photochemical formation of tricyclo{6.4.0.0('2, 7)}7, 8-cis-dodec-1-ene (CB), 1'-methoxybicyclohex-1-ene (1, 2 ET), and a new product, 2'-methoxybicyclohex-1-ene (1, 4ET), from the sensitized irradiation of 1, 1... The mechanism of photoproduct formation from the direct irradiation of BCH has also been investigated. The observed photoproducts are CB, 1, 2 ET, 4 ET and 1, 3'-bicyclohexenyl (UD). Steady state photochemical measurements of product...
Acquired immunodeficiency syndrome (AIDS) caused by the human immunodeficiency virus (HIV) is an ongoing epidemic affecting millions of people worldwide, with the majority of those infected living in poverty. Today, multiple treatment...
Part I. Further studies on the amine-directed hydrocarboxylation. Part II. Approaches to the synthesis of the alkaloid corynantheidol
Description:
Further studies on the amine directed hydrocarboxylation are presented. Hydrocarboxylation of (N-(2-butyl-3, 3-dideutero)-4-pentenyl-n-butylamine) carbonyl rhodium chloride gave rise to 1-butyl-3-methyl-4, 4-dideutero-5-butyl-2... Investigations were performed on approaches to the stereoselective synthesis of corynantheidol. Studies towards the preparation of cis 3, 4-disubstituted piperidinone key intermediates indicated that reaction of cis bishomoallylic amines...
BIOGENETICALLY PATTERNED STEREOSELECTIVE SYNTHESIS OF EUDESMOLS VIA NITRONE-OLEFIN CYCLOADDITIONS
Description:
((+OR-))-(alpha)-Eudesmol (1)* was synthesized in eleven steps from methyl farnesate (2) via the intramolecular 1, 3-dipolar cycloaddition of E-monocyclofarnesal nitrone (3). The cycloaddition of this nitrone afforded two isoxazolidines 4... The double bond isomer ((+OR-))-(beta)-eudesmol (8) was obtained when water was present in the quaternization reaction mixture of 7. This double bond isomerization was apparently initiated by a reversible deprotonation of the C-8 methyl... The synthesis of the three isomers of (alpha)-eudesmol as well as epi-(beta)- eudesmol (10) were realized from this approach. Epi-(alpha)-eudesmol(11) and the epi-(beta)- isomer 10 were obtained by the same reactionsequences from 5. The... cis-(alpha)-eudesmol (15) and cis-(alpha)-eudesmol (16). *See abstract accompanying dissertation for the structures of the numbered compounds.
The stereoelectronic control of reactivity provides a special, yet necessary challenge. Pericyclic reactions play an important role in the development of theoretical organic chemistry, and they enable many practical synthetic processes....
This dissertation describes the development of alternative products from the copper-catalyzed azide-alkyne cycloaddition (CuAAC). The first chapter provides an introduction to the CuAAC through the historic timeline of the development of...
Part I. Studies on the use of bidentate ligands in the directed Pauson-Khand reaction. Part II. The Pauson-Khand reaction in synthesis: Towards the total synthesis of asteriscanolide
Description:
Two main investigations based on the Pauson-Khand reaction were performed. The use of bidentate ligands in the directed Pauson-Khand reaction was investigated. Substrates with a three-carbon linkage between the two heteroatoms gave better results than substrates containing two-carbon tethers. Higher yields and... Investigations were performed on two main approaches towards the total synthesis of Asteriscanolide, both of which employ the Pauson-Khand reaction at a crucial juncture. Studies towards the preparation of the bridged bicyclic...
AN ORGANOTRANSITIONMETAL APPROACH TO THE SYNTHESIS OF SUBSTITUTED NAPHTHO- AND BENZOQUINONES (NAPHTHOQUINONES)
Description:
Reaction of bis(triphenylphosphine)chlorocobaltaindane-1, 3-dione with 1 equivalent of AgBF(, 4) followed by treatment with various ligands resulted in the formation of cationic phthaloylcobalt complexes. Reaction of these cationic... The information obtained from reaction studies of the phthaloyl-cobalt complexes was applied to several maleoylcobalt complexes in order to develop an organotransitionmetal approach to benzoquinone synthesis. In order to generalize such...
Cascade radical transformations of acyclic precursors that incorporate alkynes open efficient, convenient, and atom-economical access to functionalized compounds. The selective sequence of cyclizations followed by controlled termination...
This work describes the oxidation of organic compounds in an argon/water continuous flow plasma reactor. Water insoluble materials such as alkanes and alkenes, in particular n-pentane to n-octane, 1-hexene, cyclohexane and cyclohexene...
This work describes a simple and general approach to the design of new polyaromatic diradicaloids. The systematic approach starts with privileged core structures with the maximum number of Clar's sextets, and explores the electron...
The work disclosed in this dissertation explores using two-center/three-electrons and electron upconversion in C-N bond formation. In particular, three areas will be discussed in detail: 1) computation exploration into intermolecular C-N...
THE MECHANISM OF PRODUCT FORMATION IN ANTHRACENE/TRANS,TRANS-2,4-HEXADIENE SYSTEM
Description:
The photochemical reaction of anthracene (A) with trans, trans-2, 4-hexadiene (D) produces anthracene dimer (A(, 2)), a major 4(pi)+4(pi) cross-adduct (Ad), and three minor cross-adducts: Ad' (4(pi)+4(pi)), Ad'' (4(pi)+2(pi)), and Ad''' ... required a minimum number of derived parameters. These parameters describe the fate of singlet and triplet (A/D) exciplexes in cross-adduct formation ('1)(AD)*(--->) (beta) Ad + (beta)' Ad' + (1-(beta)-(beta)') (A+D); ('3)(AD)*(--->) ...
BIOMIMETIC SYNTHESES OF SEVERAL MORPHINE ALKALOID ANALOGUES
Description:
N-Ethoxycarbonyl-5'-hydroxynorreticuline (1) was oxidized with vanadium oxytrichloride (VOCl(, 3)) to give the para-ortho coupled N-ethoxycarbonyl-2-hydroxynorsalutaridine (2) in 55% yield. Dienone 2 was converted into N-ethoxycarbonyl-2-hydroxynorthebaine (3) in 47% yield. Hydrolysis of 3 gave an 85% yield of N-ethoxycarbonyl-2-hydroxynorcodeinone (4) which upon reduction produced ((+OR-))-2-hydroxycodeine (5). Reaction of the protected thebaine analogue 6 with singlet oxygen generated the protected 2, 14-dihydroxynorcodeinone derivative 7. Selective dehydroxylation with concurrent double bond reduction gave the known N...
Acid-catalyzed cyclizations of aromatic diazoacetamides
Description:
The acid-catalyzed cyclizations of various aromatic diazoacetamides were studied and general and efficient preparations of isoquinolinones, benzazepinones, and spirodienone lactams were realized. The scope and limitations of these... In the presence of anhydrous trifluoroacetic acid, $\alpha$-unsubstituted $N$-methyldiazoacetamides were cyclized to give isoquinolinones in 60-80% yield. Cyclization of the diazoacetamides under these conditions, except with immediate... Spirodienone lactams prepared by this method were demonstrated to be synthetically useful. Rearrangement of these compounds in the presence of boron trifluoride etherate in refluxing nitromethane proceeded regiospecifically to afford... The described reactions were employed in synthetic approaches to the alkaloids morphine and colchicine.
This dissertation investigates the synthesis and characterization of new bioderived polymers from a variety of different biomass sources. In one thrust, a series of new monomers and polymers are synthesized from a toxic and inedible...
Cotton effects in circular dichroism and optical rotatory dispersion spectra of 1, 3-dienes and (alpha), (beta)-unsaturated ketones, for their (pi)-(pi)* transitions, are believed to arise from inherent dissymmetry of the chromophores as...
Structural foams reinforced with carbon nanotubes could prove to be beneficial in numerous industrial applications. High internal phase emulsion foams are emerging as new and important forms of microcellular foams. Microcellular foams, ...
Fluorescence emission was observed upon excitation of highly purified cis-stilbene (99.98%) in fluid n-hexane and n-tetradecane solutions. The observed cis-stilbene emissions were deconvoluted into contributions representing fluorescence...
A Biogenetic-type total synthesis of erythro and threo-(+, -)-alpha-bisabolol. The determination of the relative stereochemistry of naturally occurring (-)-alpha-bisabolol
Some of the material in is restricted to members of the community. By logging in, you may be able to gain additional access to certain collections or items. If you have questions about access or logging in, please use the form on the Contact Page.
