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Preparation of Lupane and 18alfa-Oleanane Triterpenoids for Biological Testing
Kvasnica, Miroslav ; Šarek, Jan (advisor) ; Klinotová, Eva (referee) ; Drašar, Pavel (referee) ; Pouzar, Vladimir (referee)
T =t a a !r a a a t I a a a - - 5. CONCLUSION 5. CONCLUSION This work was focused on the synthesis of new triterpenoids - named highly oxidized derivatives of 18o-oleanane, their reductive products or products with heteroatoms, for example fluorine, nitrogen, suflur or phosphorus. Part of this thesis was focused on reactions of lupane and I 8cr-oleanane triterpenoids with Lawesson's reagent. l. Highly oxidized l8cr-oleanane derivatives were synthesised, in particular on A-ring. Commercially available reagents were used for these oxidations: MCPBA, SeOr or pero- xyacetic acid (as a persteril). A group of seco derivatives was prepared by reactions with in situ prepared RuOo. A great deal of this section has been already published in scienti- fic journal.2a 2. Agroup of 18ct-oleanane alcohols (e.g. L5,16a,16b, 19, 20,22) was prepared from some oxidized derivatives (e.g.2,3, 13, L8) by reactions with LiAlHo or NaBI{.. 3. Reactions of some ketones were carried out (e.g. 3) with fluorinating agent DAST for preparation of new fluorous derivatives (e.g. 24,25). The same ketones reacted with ethanedithiol to afford new dithiolanes (e.g. 26). Diketone 3 was'also used for synhesis of several nitrogen containing derivatives. Preparation of pyrazine 27 and quinoxaline 28 has been already published in scientific...

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