Sökning: "Alkaloids"
Visar resultat 16 - 20 av 36 avhandlingar innehållade ordet Alkaloids.
16. Synthetic studies of heterocyclic natural products
Sammanfattning : The methods that were developed for the synthesis of the heterocyclic natural products luotonin A, ophiuroidine, cephalandole B, and the indol-3-yl-benzoxazinones of cephalandole A are described in this thesis. The reoccurrence of the 4(3H)-quinazolinone structure is a common theme throughout these studies, and an overview of some quinazoline chemistry is introduced in the first chapter. LÄS MER
17. Application of metalation reactions for synthesis of sulfur/selenium-containing heterocyclic compounds
Sammanfattning : This thesis deals mainly with the synthesis of various sulfur/selenium-containing heterocyclic compounds, many of which include structural features present in several biologically active molecules, with particular emphasis on compounds of synthetic importance, such as indoles, as well as other heteroaromatic species. In the first part, an efficient procedure toward synthesis of new 3-(arylthio)indoles based on reactions of aryl Grignard reagents or lithiated heteroaromatics with protected 3,3′-dithiobisindoles is described. LÄS MER
18. Harm and harm reduction in smokeless tobacco users. An in vitro and clinical study
Sammanfattning : Background: This thesis describes the effects of smokeless tobacco (ST) and its derivatives on the oral mucosa; the development of, and results of applying a cessation program for snuff users with long and extensive exposure; and the persistent clinical and histomorphological changes after cessation. Methods: Three of the studies were open prospective non-randomized clinical intervention trials using nicotine replacement therapy (NRT) of either 4 mg nicotine chewing gum or 2 mg nicotine lozenges. LÄS MER
19. Carbon-Carbon Bond Formation via Radical Cyclization and Transition Metal Catalysis
Sammanfattning : Free radical cyclization methodology has been used extensively in synthesis for manipulation of complex molecules such as alkaloids, terpenes, carbohydrates, peptides and nucleic acids. The methodology has emerged as a result of work by physical organic chemists who determined rate constants for the most common radical reactions used in organic synthesis. LÄS MER
20. Metal-Free Catalysis for Efficient Synthesis
Sammanfattning : The strength of efficient metal-free catalysis will be examined in this thesis. Efforts towards more sustainable processes will be demonstrated through implementation of strategies that meet several of the 12 principles of Green Chemistry. LÄS MER
