• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 22
  • 10
  • 3
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 54
  • 19
  • 18
  • 18
  • 8
  • 8
  • 7
  • 7
  • 6
  • 6
  • 6
  • 6
  • 6
  • 5
  • 5
  • 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.
1

Formation of N-nitrosopyrrolidine from various pyrrolidine ring-containing compounds at elevated temperatures

Huxel, Edward Thomas 01 May 1973 (has links)
Graduation date: 1973
2

Novel syntheses of nitrogen heterocycles

Jones, A. D. January 1997 (has links)
No description available.
3

Methodology for the synthesis of biologically important molecules

Bailey, Jonathan Henry January 1994 (has links)
No description available.
4

The asymmetric synthesis of polyfunctional pyrrolidine alkaloids and their analogues

Lindsay, Karl B. January 2003 (has links)
Thesis (Ph.D.)--University of Wollongong, 2003. / Typescript. Includes bibliographical references: leaf 214-222.
5

The chemistry and use of pyrroline ring systems in the synthesis of natural products /

Persichini, Phillip John, January 1994 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Includes bibliographical references (leaves 26-29). Also available via the Internet.
6

Cyclisation reactions mediated by sulfur-stabilised cations

Pecheux, Muriel January 1995 (has links)
No description available.
7

synthesis of bipyrrole-pyrrolidine

Lin, Chun-yu 25 July 2008 (has links)
Polyamide containing groove binding agents have been widely reported. We synthesized pyrrolidine to displace one of pyrrole of distamycin, and research into structure which was effected by optical and saturated heterocycle.
8

Investigations in dienamine chemistry.

Simpson, Richard. January 1991 (has links)
Reaction of the pyrrolidine dienamines of ~1,8a-2-octalones with methyl vinyl ketone is complex. In methanol as solvent, the reaction occurs primarily with the linear dienamine isomer and results in annulation of the 8,8a-positions and, to a lesser extent, the 1,2-positions to give the corresponding octahydro-1 Hbenzo[d]naphthalene-2,10(3H,111-1)-dione and 3,4,5,6,7,8,8a,9-ctahydrophenanthren-2(10H)-one respectively. In toluene the dienamines react mainly in their cross-conjugated form. Diels-Alder addition of methyl vinyl ketone occurs across the 3,8a-positions to give the corresponding 9-acetylperhydro-2,4aethanonaphthalen-3-one and annulation of the 2,3-positions gives the 4,4a,5,5a,6,7,8,9-octahydroanthracen-2(3H)-one. The reaction of methyl vinyl ketone with the pyrrolidine dienamine of 4amethyl- 5-oxo-~ 1,8a-2-octalone is reported to give the aromatic product 3a, 7dimethyl- 2,3,3a,4,5,6-hexahydrophenalen-3,6-dionearisingfromp,o-annulation and in a related investigation with dienamines derived from isophorone it was reported that only products of Stork alkylation and Diels-Alder cycloaddition were isolated, there being no evidence for the reaction of methyl vinyl ketone with either the endo- or exocyclic o-positions of the dienamines. In an attempt to ascertain the reason for the apparently random changes in the regioselectivity of these related reactions some of this work was repeated and the reaction of methyl vinyl ketone applied to two other dienamines derived from 5,6,7,7a-tetrahydroindan-5-one and 4a,6-dimethyl-5-oxo-~1,8a-2-octalone. The reactions proved to be more complex than reported and several additional products have been isolated. Finally, reaction of phenyl vinyl ketone with dienamines derived from a1,8a_2-octalone was investigated. With the exception of the reaction of the 4amethyl dienamine, the main products isolated were those arising from addition of p.henyl vinyl ketone across the 3,8a-position to give the corresponding 9-benzoylperhydro-,4a-ethanonaphthalen-3-one. Reaction of the 4a-methyl dienamine with two equivalents of phenyl vinyl ketone gave a product tentatively assigned as the octahydrophenalenone. The mechanism of formation and spectral properties of the various products are discussed. / Thesis (Ph.D.)-University of Natal, 1991.
9

Studies on higher sugars

Beacham, Annabel R. January 1994 (has links)
This thesis describes the synthesis of three novel seven carbon bicyclic mimics of α-L-fucose, and of two new pyrrolidine amino sugars. 2,7-Anhydro- l-deoxy-β-L-gulo-heptulopyranose and l,2,7-trideoxy-2,7-imino-β- L-gulo-heptulopyranose were both synthesised from L-gulono-l,4-lactone. The addition of one equivalent of methyllithium to the diacetonide of L-gulono-1,4- lactone gave a keto-sugar, l-deoxy-3,4;6,7-di-0-isopropylidene-β-L-gulo- heptulofuranose. The anomeric configuration of this compound was determined by equilibrium nOe measurements. Hydrolysis in aqueous trifluoroacetic acid caused simultaneous deprotection, isomerisation and dehydration to yield 2,7-anhydro-l-deoxy-β-L-guloheptulopyranose, a highly stable, rigid bicyclic system. The structure of the bicyclic system was confirmed by X-ray crystallographic studies on a crystalline derivative. The introduction of nitrogen at C-6 of L-gulono-l,4-lactone was achieved via the azide displacement of the known bromide, 6-bromo-6-deoxy-2,3-0- isopropylidene-L-gulono-l,4-lactone. Protection of the C-5 hydroxyl group as its silyl ether was followed by the addition of one equivalent of methyllithium to the carbonyl group to give a keto-sugar, 7-azido-6-(0-tert-butyldimethylsilyl-l,7- dideoxy-3,4-0-isopropylidene-β-L-gulo-heptulofuranose. Removal of the protecting groups followed by reduction of the azide functionality gave the bicyclic hemiaminal, l,2,7-trideoxy-2,7-imino-β-L-gulo-heptulopyranose, a stable but hygroscopic solid. A third bicyclic system, 2,7-anhydro-l,2,6-trideoxy-2,6-imino-β-L-gulo- heptulopyranose, was synthesised from diacetone-D-mannose via the known ketosugar, 6-azido-7-0-tert-butyldimethylsilyl-l,6-dideoxy-3,4-0-isopropylidene-β- L-gulo-heptulofuranose. Removal of the protecting groups from this keto-sugar, followed by reduction of the azide functionality, gave the target system. Analysis of the NMR spectra showed that this existed as an equilibrium mixture of the closed, bicyclic hemiaminal form and the monocyclic imine form, with the bicyclic form predominating in all solvents investigated. The sodium borohydride reduction of l-deoxy-3,4;6,7-di-0-isopropylidene-β-L-gulo-heptulofuranose gave a single product, the heptitol 7-deoxy-l,2;4,5-di-0-isopropylidene- L-glycero-D-gluco-heptitol. This was converted into two novel pyrrolidine amino sugars, l,2,5-trideoxy-2,5-imino-L-glycero-L-allo-heplitol and l,2,5-trideoxy-2,5-imino-L-allitol. The two free hydroxyl groups in the heptitol were converted into leaving groups and one was then displaced selectively with sodium azide. Reduction of the azide functionality gave an amine which cyclised onto the remaining leaving group to form the pyrrolidine framework. Complete deprotection of this product gave l,2,5-trideoxy-2,5-imino-L-glycero-L-allo- heptitol, the structure of which was confirmed by X-ray crystallographic studies on a crystalline derivative. Removal of the primary acetonide from the cyclisation product and subsequent periodate cleavage gave an aldehyde which was then reduced to an alcohol. Deprotection then gave the second pyrrolidine amino sugar l,2,5-trideoxy-2,5-imino-L-allitol. The effect of all five target compounds on eleven human liver glycosidase enzymes was investigated, and these results are also reported.
10

Chiral cyclic derivatives of C2-symmetrical butanedioic acids

Vries, Ton René. January 1996 (has links)
Proefschrift Rijksuniversiteit Groningen. / Met lit.opg. - Met samenvatting in het Nederlands.

Page generated in 0.0532 seconds