Date on Master's Thesis/Doctoral Dissertation

5-2012

Document Type

Doctoral Dissertation

Degree Name

Ph. D.

Department

Chemistry

Degree Program

Chemistry, PhD

Committee Chair

Hammond, Gerald B.

Author's Keywords

Alkyne; Agent; Selectfluor; Amazonian; Cytotoxic

Subject

Alkynes

Abstract

Vicinal dithioethers and alkenyl thioethers were synthesized under environmentally friendly conditions using alkyne and thiol in water. Alkynes were also used to develop a multibond-fonning reaction that fonned cyclic ketones or ketoesters through a goldcatalyzed intramolecular oxygen transfer isomerization of 2-alkynyl-l ,5-diketones or 2- alkyny 1-5 -ketoesters. The investigation of Selectfluor chemistry yielded a highly stereoselective synthesis of fluoroalky (E)-a,ß-unsaturated ketones from allenyl esters, through a gold-catalyzed rearrangement that produced an intennediate dienyl ester. When Selectfluor was combined with copper, it produced two oxidative systems, F-TEDA-BF4 and F-TEDAPF 6, both of which efficiently converted amides into imides at room temperature in short time, but whereas the fonner employed stoichiometric amounts of copper(I), the latter only needed catalytic amounts. The bioassay-directed fractionation of Physalis angulata L. afforded three new antiproliferative withanolides: physangulidines A, B and C. Each has shown significant cytotoxic activity (GI50 is less than 4µg/mL) on DUI45 and RWPE-I in vitro. In addition, compared to positive drug 5-fluorouracil, physangulidine A had significant cytotoxic activity on different cells. The bioassay-guided fractionation of Cremastosperma microcarpum led to the isolation and identification of dehydrodiisoeugenol as its main cytotoxic agent. Lastly, selected fractions of Hyptis lantanaefolia have shown promising cytotoxic activities; with one of semi purified chromatographic fraction (LHL 15) exhibiting very high bioactivity on various cell lines (IC50 is lower than 50 ng/mL).

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