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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

The development and evaluation of an individualized learning programme for the teaching of organic chemistry at form six level.

Hung Ip, Kit-lin, Margaret. January 1977 (has links)
Thesis--M. Phil., University of Hong Kong, 1978. / Copy 2 xerox copy of typescript. Typescript.

Origins of the structural theory in organic chemistry

Rocke, Alan J., January 1900 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / Vita. Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Synthesis and reactivity of organotantalum complexes containing nitrogen ligation

Fox, Peter Anthony, 1965- January 1996 (has links)
This work examines various aspects of hydrodenitrogenation catalysis. Various tetrahydroquinolinyl (THQ) and indolinyl (DHI) complexes of tantalum were synthesized including: Ta(THQ)ₓCl₅₋ₓ(x = 1 to 5), Ta(DHI) ₓCl₅₋ₓ(THF) (x = 1 and 2). In addition, THQ and DHI complexes containing aryloxide (OAr = 2,6-diisopropylphenoxide) and alkyl complexes were also synthesized: Ta(THQ)(OAr)Cl₃(OEt₂), Ta(THQ)₂(OAr)₂Cl, Ta(THQ)(OAr)R₃Cl (R = Me and Et), Ta(THQ)₂(OAr)₂R (R = Me and Et), Ta(DHI)(OAr)Cl₃(OEt₂), and Ta(DHI)₂(OAr)₂Cl. The effects of sulfur ligation versus oxygen ligation was examined by comparison of the crystal structures of Ta[η²(N,C)-2,4,6-tri-t-butylpyridinel](OAr)₂(OᵗBu) and Ta[η²(N,C)-2,4,6-tri-t-butylpyridine](OAr)₂(SᵗBu). The sulfur ligand donates less π density to the metal center, resulting in a longer Ta-C bond for the pyridine ligand. The arene complexes (η⁶C₆Me₆)Ta(OAr)(SAr')Cl and (η⁶-C₆Me₆)Ta(OAr)(SAr'')Cl were also synthesized. These arene-thiolate complexes do not appear to bind quinoline, unlike the oxygen analogs A number of Ta(η⁴-diene)(OAr)₃ complexes were synthesized (diene = butadiene, isoprene, 2,3-dimethylbutadiene, 1,3-cyclohexadiene) and their reactivity with respect to nitriles examined. Nitriles typically insert into Ta(η⁴-isoprene)(OAr)₃ to form (ArO₃Ta(CH₂CHCMeCH₂CRN) which can then be thermally rearranged to (ArO) ₃Ta(=NCRCH₂CHCMeCH₂) (R = Me, Ph, ᵗBu). Similar reactivity is observed with butadiene and 2,3-dimethylbutadiene diene complexes. The Ta(η⁴-C₄H₆)(OAr)₃ complex is also capable of inserting two nitriles to form (ArO)₃Ta(NCRCH₂CHCHCH₂CRN), whereas Ta(η⁴-1,3-cyclohexadiene)(OAr)₃ only forms the bis-insertion product. Aspects of the formation of the above complexes with specific concentration on the tantalum-nitrogen interactions are presented.


Unknown Date (has links)
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-ethoxycarbonylnoroxycodone (8); subsequent hydrolysis of 8 then concluded the total synthesis of ((+OR-))-noroxycodone (9). / Source: Dissertation Abstracts International, Volume: 42-01, Section: B, page: 0225. / Thesis (Ph.D.)--The Florida State University, 1981.

Process Improvement of Rac-Progesterone and Other Synthetic Studies

Unknown Date (has links)
This thesis describes the work performed by the author during PhD studies at FSU. The first two chapters present the summary of the studies done trying to accomplish the first total synthesis of aldingenin B - a natural product first isolated in 2003. While our studies were ongoing, some additional information on the structure of the natural product emerged, therefore our studies and their relationship with the literature available up to 2015 are discussed in detail. Chapters 3 through 6 represent the main topic of the thesis. They focus on the studies directed towards the development of the efficient synthesis of ent-progesterone - a potential drug candidate for the treatment of traumatic brain injury. Chapter 3 introduces the problem and the necessity for such synthesis and reviews the literature relevant to the topic. Chapter 4 presents an improved synthesis of rac-progesterone - an important step in the synthesis of ent-progesterone. Chapter 5 compares the efficiency of the two approaches: an old one and the improved route. / A Dissertation submitted to the Department of Chemistry and Biochemistry in partial fulfillment of the Doctor of Philosophy. / Spring Semester 2015. / April 29, 2015. / aldingenin B, benzylation, ent-progesterone, process improvement, progesterone, total synthesis / Includes bibliographical references. / Gregory B. Dudley, Professor Directing Dissertation; John Telotte, University Representative; Tyler McQuade, Committee Member; Sourav Saha, Committee Member; Michael Shatruk, Committee Member.

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

Unknown Date (has links)
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 better regioselectivities were observed with thioamines and bisthioethers compared to diamines. Overall, only a few bidentate substrates showed marked improvements over previous results obtained with analogous monodentate compounds. Rationalizations based on the possible modes of cycloaddition operative for the various substrates studied are presented. / 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 intermediate needed for the key cycloaddition reaction in the first strategy were not encouraging. Intermolecular Pauson-Khand reactions of alkynoate complexes were studied towards developing a useful methodology for use within the second synthetic scheme. The amine oxide-promoted reaction between propene and (ethyl 5- (t-butyldimethylsilyl) oxy)-2-pentynoate)dicobalthexacarbonyl gave the desired cyclopentenones in $>$30:1 ratio and 90% yield. Succeeding steps were performed in excellent yield. Attempts to reduce the double bond in a number of intermediates are described. / Source: Dissertation Abstracts International, Volume: 55-04, Section: B, page: 1438. / Major Professor: Marie E. Krafft. / Thesis (Ph.D.)--The Florida State University, 1994.

Synthetic studies toward the total synthesis of taxol. (Volumes I and II)

Unknown Date (has links)
The use of a total synthesis of taxol for producing a supply of taxol, while not a viable option at the present, may someday aid in the development of second generation taxoid drugs that are more potent and have less side-effects. This dissertation will describe synthetic studies undertaken by this researcher towards the total synthesis of taxol. The research described in Part I and Part II will cover photochemical studies designed to address the problem of synthesis of the D-ring oxetanol of taxol. The Norrish II photocyclization of a C-ring $\alpha$-methoxy ketone to produce an oxetanol will be discussed in Part I, and a Paterno-Buchi photocyclization of an aldehyde and an enol acetate will be discussed in Part II. In Part III, a methodology for the oxidation of C-9 and C-10 of taxol using a protocol based on the benzeneseleninic anhydride oxidation of an enolate via a 2,3 sigmatropic rearrangement is described. / Source: Dissertation Abstracts International, Volume: 55-09, Section: B, page: 3892. / Major Professor: Robert A. Holton. / Thesis (Ph.D.)--The Florida State University, 1994.

New applications of the Michael reaction. An approach to the synthesis of gelsemine. Synthesis of taxane diterpenes

Unknown Date (has links)
Part one describes a study undertaken to extend the synthetic application of the Michael reaction. This involved developing methodology that enabled construction of vicinal quaternary centers via the Michael reaction. In addition, factors influencing diastereoselectivity in additions of enolates to $\alpha$-(phenylthio)butenolide were examined. / A palladium-mediated approach to the alkaloid gelsemine is described in part two. New Lewis acid mediated carbonylation chemistry had to be developed for this project. This chemistry was applied to several representative examples to demonstrate its generality. / Part three relates the details of part of a total synthesis of taxusin, a simple taxane diterpene. The remainder of part three is devoted to a description of ongoing efforts towards the total synthesis of taxol, a potent antitumor agent and the most complex member of this class of compounds. / Source: Dissertation Abstracts International, Volume: 53-11, Section: B, page: 5729. / Major Professor: Robert Holton. / Thesis (Ph.D.)--The Florida State University, 1989.


Unknown Date (has links)
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 complexes with alkynes produced naphthoquinones. Comparison of the structure and reactivity of various cationic cobalt complexes led to several important conclusions regarding the mechanistic nature of the quinone forming reaction. These conclusions were used as a guide in the design of a neutral phthaloylcobalt complex featuring a diequatorially coordinated dimethylglyoxime ligand which was found to give high yields of substituted 1,4-naphthoquinones on treatment with functionalized alkynes. Addition of 1 equivalent of CoCl(,2)(.)6H(,2)O was found to significantly increase the reaction rate of the neutral cobalt complexes. / 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 a synthetic route, a general synthesis of substituted cyclobutenediones adaptable to the synthesis of multigram quantities of dione was developed. This synthesis was based on a cyclo-addition reaction of dichloroketene with vinyl sulfides. The resulting cycloadducts underwent an unusual elimination-readdition sequence resulting in the formation of 4-thiophenyl-2-chlorocyclobut-2-ene-1-ones which on oxidation with MCPBA underwent a {2,3}sigmatrophic shift to afford substituted cyclobutenediones. Several of these diones were converted to maleoyl dimethylglyoxime complexes which gave good yields of substituted benzoquinones on treatment with alkynes. / Source: Dissertation Abstracts International, Volume: 45-01, Section: B, page: 0185. / Thesis (Ph.D.)--The Florida State University, 1984.


Unknown Date (has links)
Investigations of the triplet states of 1-phenyl-2-(2-naphtyl) ethylene (2-NPE), under steady-state conditions in the presence of competing energy-transfer and spin-exchange quenchers have allowed obtention of effective triplet lifetimes, and decay parameters. Direct transient observations, done in collaboration with H. Gorner, have confirmed the steady-state results, as well as defined triplet state parameters for two distinct 2-NPE species. Investigations of both types on conformationally restricted analogs, representative of conformers formed by 1-(alpha) rotation of the 2-naphthyl moiety, have confirmed the identification of the two 2-NPE species as conformational isomers. / Studies in the excited singlet manifold have focused on separation and independent treatment of the properties of the multiple emissive 2-NPE species. Observations of fluorescence spectra under conditions of variable excitation wavelength, temperature, viscosity, and added singlet state quenchers were performed and quantitated in terms of component contributions by application of Principal Component Analysis (PCOMP); which determines the number of significant contributing species, their intrinsic spectra, and their relative amounts without any prior knowledge of component properties. Again, similar studies performed on the conformationally defined analogs, have indicated their similarity to the 2-NPE species observed and indicate their formation via the proposed ground state conformational equilibrium. Aside from confirming the previously proposed ground state conformational control of excited state behavior, the detailed analysis strongly suggests the dynamic involvement of allowed and forbidden pairs of states within each excited conformer. / In addition, photochemical investigations of all substrates in both the singlet and triplet manifold have provided evidence for direct cis-trans isomerization via the excited singlet, as well as exhibiting behavior in many respects similar the the symmetrical homolog, stilbene. In all cases, correlation of 2-NPE comformer behavior to that of the analogs has been successful, and suggests a direct effect of single-bond rotation in determining excited state properties. Analysis of this effect in terms of excited transitions and energetics is proposed to account for the observations. / Source: Dissertation Abstracts International, Volume: 45-04, Section: B, page: 1194. / Thesis (Ph.D.)--The Florida State University, 1984.

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