• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 30
  • 7
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 50
  • 50
  • 7
  • 6
  • 6
  • 5
  • 5
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 2
  • 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.
31

Azo-anions in organic synthesis

Newington, Ian M. January 1985 (has links)
Novel synthetic applications of ambident azo-anions derived from hindered hydrazones have been investigated. Reaction with electrophiles occurred predominantly at carbon as the N-addition pathway was sterically retarded. Trityl, diphenyl-4-pyridylmethyl (DPP) benzhydryl, and t-butyldiphenylmethyl (BDP) hydrazones of various aldehydes and ketones were prepared in good yields from the corresponding hydrazines and carbonyls in aqueous methanol. The lithium salts derived from trityl and DPP hydrazones, by treatment with methyl lithium at -55°C, reacted with aldehydes and ketones to generate azo-alkoxides. These could be diverted to alcohols,by sequential protonation and spontaneous homolysis (about -20°C) in the presence of ethanethiol, or to alkenes,by treatment with phosphorus trichloride at -78 G followed by azo-homolysis. The reactions enabled efficient reductive cross-coupling of aldehydes and ketones. The mechanism of the alkene forming reaction was investigated. Anions of benzhydryl hydrazones were found to react inefficiently by a G-addition pathway giving mainly N-addition products. Anions of BDP hydrazones conveniently gave excellent yields of azo-alkanes upon treatment with alkyl halides,but no products were obtained on reaction with carbonyl electrophiles. The azo-alkanes could be isolated and purified and acted as key intermediates for several synthetically useful transformations. Homolysis in refluxing benzene with thiophenol gave alkanes in good yields. Phenylselenenyl-, bromo-, and chloro-alkanes,and β-alkylstyrenes were generated when thiol was replaced by diphenyl diselenide, N-bromosuccinimide, N-chlorosuccinimide and β-nitrostyrene respectively. Treatment of the azo-alkanes with trifluoroacetic acid generated benzophenone alkylhydrazones. These were dissolved in ethanol with concentrated hydrochloric acid, thereafter hydrolysis yielded alkylhydrazines or treatment with hydrogen (1 atm., 50°C, 20h) over 10% Pd/C generated primary amines by a novel use of carbonyls as α-aminocarbanion equivalents.
32

Kinetic and equilibrium studies of cyclodextrin-azo dye inclusion complexes /

Clarke, Ronald James, January 1985 (has links) (PDF)
Thesis (Ph. D.)--University of Adelaide, Dept. of Physical and Inorganic Chemistry, 1985. / Offprints of two author's journal articles inserted at end of the v. Includes bibliographical references (leaves 10-12).
33

A study of bibracchial lariat ether complexes and linked cyclodextrin dimer complexes /

West, Lee Charles. January 2000 (has links) (PDF)
Thesis (Ph.D.) -- University of Adelaide, Dept. of Chemistry, 2000. / Includes errata attached to first leaf. Includes bibliographical references.
34

Modulation of intracellular GSH in THP-1 cells during oxidative stress induced by AAPH : a thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Biochemistry, University of Canterbury, Christchurch, New Zealand /

Brown, Erin January 2006 (has links)
Thesis (M. Sc.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references (leaves 71-79). Also available via the World Wide Web.
35

m-aminocyclohexanol

Law, Leroy Mancel 01 January 1961 (has links)
There has developed in recent years an interest in chemical materials that may have the ability to concentrate in and about carcinomic tissue.
36

The kinetics of thermal decomposition of 1,1'-Azobutane, 1,1'-Azoisobutane and 2,2'-Azobutane

Eatough, Norman L. 06 May 1959 (has links)
The following compounds have been prepared and purified and the boiling points, densities, refractive indicies and infrared spectra of each have been determined and recorded: n-butyraldazine, isobutyraldazine, methylethyl ketazine, 1,2-di-n-butylhydrazine, 1,2-diisobutylhydrazine, 1,2-di-sec.-butylhydrazine, 1,1'-azobutane, 1,1'-azoisobutane and 2,2'-azobutane. Vapor pressure curves and freezing points of 1,1'-azobutane, 1,1'-azoisobutane and 2,2'-azobutane have been determined and recorded. The kinetics of thermal decomposition of 1,1'-azobutane, 1,1'-azoisobutane, and 2,2'-azobutane in a flow system using hydrogen and helium as a carrier gases have been investigated. The investigation was carried out for two different concentrations of the azo compounds over a pressure range of 670 to 890 mm. Hg and a temperature range of 260° to 380° C. The decomposition reactions were found to be first order in all cases. The appropriate first order rate expressions have been determined and recorded for the decompositions. The concentrations of the azo compounds were in the range of one to six mole per cent. The first order rate constant for the decomposition of the three azo compounds at a concentration of 1.1 mole per cent in helium are as follows: 1,1'-Azobutane: k = 1.3 x 1017 x e-51,600/RT 1,1'-Azoisobutane: k = 1.6 x 1016 x e-46,200/RT 2,2'-Azobutane: k = 1.8 x 1017 x e-48,200/RT The reaction rate constants, the energies of activation based on a collision theory and the entropies and enthalpies of activation based on the absolute reaction rate theory have been determined and recorded for the three azo compounds. The products of decomposition have been investigated using gas chromatography. The results of these investigations have shown that the decomposition process is complex. Several reactions have been postulated to explain the presence of these decomposition products.
37

The chemistry of Osmium carbonyl clusters containing organomercurials and azo-compounds

江鳳思, Kong, Fung-sze. January 1999 (has links)
published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy
38

Routes to novel azo compounds

Iannarelli, Paul M. January 2008 (has links)
Routes to novel heterocyclic azo compounds and components of use as potential inkjet dyes were investigated. A new route to fluorenones from biphenyl acid chlorides using FVP (Flash Vacuum Pyrolysis) has been discovered. Fluorenone and 4-methylfluoren-9-one were prepared by FVP of 2-phenylbenzoyl chloride and 2-methylbiphenyl-2-carbonyl chloride respectively. Xanthen-9-one and thioxanthen-9-one were also prepared by FVP from the corresponding acid chlorides. 9-Phenanthrol could also be prepared via the FVP of biphenylacetyl choride and the application of this method to a heterocylic thiophene system afforded naphtho[1,2-b]thiophen-4-ol. Naphtho[2,1-b]thiophen-4-ol and naphtho[1,2-b]furan- 4-ol could be obtained in low yields by the FVP of (2-thiophen-3-ylphenyl)acetic acid methyl ester and (2-furan-2-ylphenyl) acetic acid methyl ester over a tungsten trioxide catalyst. Coupling of these systems with the diazonium salt of Acid Yellow 9 afforded the corresponding azo compounds. New heterocyclic dyes were also prepared from the condensation of heterocyclic hydrazines with 4,9-disulfophenanthrenequinone. Pyridine, pyridazine, phthalazine, isoquinoline and 2-quinoline disulfophenanthrene quinone metallised 2:1 nickel complexed magenta dyes were prepared. Industrial tests by standard methods revealed the pyridazine dye has a particularly impressive balance of light and ozone fastness over similar magenta dyes. The reaction of an arylnitro compound with 2-aminopyridine appeared to be an attractive and high yielding route to 2-(phenylazo)pyridine. However, application of this reaction to substituted and naphthalene systems failed. This afforded byproducts due to nucleophilic substitution of groups such as methoxy and the relatively uncommon nucleophilic substitution of hydrogen with none of the required azo products obtained. Therefore it appeared that the reaction of a nitro and amine was not a robust and versatile route to heterocyclic azo compounds. An alternate route to heterocyclic azo compounds involved the use of the Mills reaction by the condensation o-anisidine, p-chloroaniline, 2-aminophenol, 3- aminophenol, naphthylamine, 8-amnioquinoline and 2-acetylamino-5-aminobenzenesulfonic acid with 2-nitrosopyridine afforded the heterocyclic azo products in moderate to high yields. The Mills reaction does appear to be the favored route to heterocyclic azo compounds. Several factors were identified which affect the process of bisazo coupling of chromotropic acid and products obtained. Reaction at the ipso position of monoPACAs (2-phenylazochromotropic acid) leading to increased yields of the ipso substitution monoPACA by-product as opposed to the expected bisazo coupling position was a major problem. Studies indicated reactivity at the ipso position was greatly reduced by the presence of electron withdrawing groups around the phenyl ring of the monoPACA. Further study indicated reaction at the bisazo coupling position increased with the strength of the diazonium salt used in bisazo coupling. Therefore the electronic nature of the monoPACA starting material and the diazonium salt used in bisazo coupling greatly affected the products obtained. Reaction pH studies also revealed attack at the bisazo coupling position increases with pH and at lower pH (5.0 – 8.0) attack at the ipso position dominated. Reactivity of the monoPACA starting material also increased with pH. The influence of steric effects upon bisazo coupling revealed, in the cases where ortho sulfonic acid groups were present in the monoPACA, a reduction in attack at the ipso position. Hence the reaction appeared to be directed towards the required bisazo coupling position.
39

A study of bibracchial lariat ether complexes and linked cyclodextrin dimer complexes

West, Lee Charles. January 2000 (has links) (PDF)
Includes errata attached to first leaf. Includes bibliographical references. The complexation of a range of monovalent and divalent metal ions by the bibracchial lariat ethers has been investigated. Also investigates the complexation of metal ions and the anionic azo dye Brilliant Yellow by the diazacrown linked cyclodextrin dimers.
40

Kinetic and equilibrium studies of cyclodextrin-azo dye inclusion complexes / Ronald James Clarke

Clarke, Ronald James, 1947- January 1985 (has links)
Offprints of two author's journal articles inserted at end of the v. / Bibliography: leaves 10-12 / 216 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physical and Inorganic Chemistry, 1985

Page generated in 0.0634 seconds