Indole alkaloids are widely found from the nature. Many indole alkaloids show physiological activity and they can be used e.g. as anti-inflammatory agents and ß-adrenergic blockers. Since their isolation is not very profitable and the obtained isolated amounts are relatively small they have to be synthesized. There are many total syntheses reported for the pharmacologically important indole alkaloids. Microwave-assisted reactions are in the main focus in this licentiate thesis. Microwaves are abundantly used in organic syntheses. Microwaves speed up the reactions by transferring the energy directly to reacting molecules. Microwave assisted methods have enabled environmentally friendly reactions. Also solvent free reactions are possible. Reactions are also reproducible due to temperature and pressure control. Tangutorine is a biogenetically interesting indole alkaloid because to date it is the only known natural product containing the benz[f]indolo[2,3-a]quinolizidine unit. It was isolated from Nitraria tangutorum by Duan et al. in 1999. So far seven total syntheses as well as two formal syntheses and two synthetic approaches of tangutorine have been published. In this licentiate thesis the first microwave assisted total synthesis of tangutorine containing six steps where three of them were done with microwave irradiation is reported. In addition to microwave-assisted total synthesis of tangutorine, microwave-assisted monoacetal and -thioacetal protections of symmetrical dialdehydes are reported.
|Tila||Julkaistu - 2013|