• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 105
  • 33
  • 24
  • 15
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 5
  • 5
  • 4
  • 2
  • 1
  • Tagged with
  • 228
  • 35
  • 33
  • 31
  • 29
  • 19
  • 19
  • 14
  • 14
  • 14
  • 11
  • 11
  • 11
  • 11
  • 10
  • 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

Approche à la synthese de phosphates cycliques : étude d'un nouveau groupement pour la protection des amines

Boivin, Joan. January 1984 (has links)
No description available.
32

A Study of the Synthesis and Reactions of Enol Lactones

Papalos, John George 08 1900 (has links)
The purpose of this investigation was to study the syntheses of enol lactones and to prepare a series of amide derivatives of these compounds.
33

Studies in the synthesis of cyclopentanoid sesquiterpene natural products

Telfer, S. January 1984 (has links)
No description available.
34

An investigation of some oxygen heterocycles : their polymerisation and effect on polymer properties

Clarkson, Richard John January 1996 (has links)
No description available.
35

Quorum sensing in Yersinia pseudotuberculosis

Buckley, Catherine M. F. January 2002 (has links)
No description available.
36

Radical cyclizations : an approach to the bryostatins

Munt, Simon Peter January 1990 (has links)
No description available.
37

De novo asymmetric syntheses of biologically important natural products phomopsolide D, phomopsolide E, milbemycin [beta]₃ and apicularen A /

Li, Miaosheng. January 1900 (has links)
Thesis (Ph. D.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains viii, 161, [213] p. : ill. Includes abstract. Includes bibliographical references (p. 154-161).
38

Studies on Bioactive Sesquiterpene Lactones From Eupatorium hualienense, Ou, Chung & Peng

Jang, Jiun-yang 28 July 2004 (has links)
Sesquiterpene lactones contain £\,£]-unsaturated-£^-lactone as a major structural feature, which in recent studies have been shown to be associ- ated with anti-tumor, cytotoxic, anti-microbial and phytotoxic activities. Previous researchers isolated sesquiterpene lactones from Eupatorium formosanum Hay. Thus, we studied Eupatorium hualienense, a unique speces in Taiwan that grows near the eastern coast. Five new sesquiter- pene lactones of the germacranolide type, eupahualins A-E (1-5) along with the known lactone, eupasimplicin B (6). Their structures were determined by 1D-NMR(1H-NMR,13C-NMR) and 2D-NMR(COSY¡BNOESY¡BHMQC¡BHMBC). Eupahualin A (1) exhibits an aldehyde at C-10 and an a,b-unsatura ted acyl group at C-8. Eupahualin B (2) also has an aldehyde at C-10. The Z-form of C-4, C-5 double bond in eupahualin B (2) is the main difference from the trans-form C-4, C-5 double bond in eupahualin A (1). The difference of eupahualin C (3) and eupahualin A (1) lies in structure of a ester group at C-8. The methyl at C-4' in eupahualin A (1) was changed into hydroxy methyl while the hydroxy methyl of eupahualin A (1) was changed to methyl in eupahualin C (3). Eupahualin D (4) shows exocyclic double bond at C-10, OH at C-1 and OAc at C-3. An carboxylic group (COOH) at C-10 in eupahualin E (5) is the only difference from which in eupahualin A (1).
39

The structure of avicennin : a coumarin from the bark of Zanthoxylum avicennae DC /

Lee, Cheuk-man. January 1957 (has links)
Thesis (M. Sc.)--University of Hong Kong, 1957. / References: p.48-51. "The occurrence of triterpenes in the aquifoliaceae and ericacear of Hong Kong, by H.R. Arthur, C.M. Lee and C.N. Ma" in pocket on inside of back cover. Type-written copy.
40

The mechanism of the ring-opening polymerization of ε-caprolactone using tin(IV) carboxylates

Bassi, Mitchell Brian, 1963- January 1987 (has links)
The polymerization of epsilon-caprolactone using tin(IV) carboxylates has been investigated and related to literature research. Polymers with broad MWD were obtained in quantitative yield. At 100% conversion polymer molecular weights ranged from 50,000 to almost 60,000. After an initial induction period, the polymerization shows zero order kinetics with respect to monomer and near first order kinetics with respect to catalyst. The mechanism of the polymerization is coordination-type, and is dependent on the presence of water or an alcoholic initiator. Added water decreases polymer molecular weight to approx. 30,000 at 100% conversion. The polymer has a terminal hydroxyl group and a terminal carboxyl group. The hydroxyl end is the reactive end in propagation. The carboxyl end and free carboxylic acid produced by the hydrolysis of the catalyst are responsible for the induction period.

Page generated in 0.4171 seconds