| Summary: | 碩士 === 淡江大學 === 化學學系碩士班 === 102 === Flavonols are naturally occurring molecules. They are recognized as good antioxidants. Many flavonols are used for reactive oxygen species scavengers, oxidase inhibitors and anticancer drugs.
Aminoflavonols are relatively rare to be found in nature, and their purification from natural products is not practical. Therefore we employed flavonols as the main framework to synthesize aminoflavonols. We utilize bromoaromatic compound as starting material. The key steps were employed aldol condensation, followed by Algar-Flynn-Oyamada oxidation (AFO oxidation) to synthesize bromoflavonols. Subsequently, the bromine group was replaced with amino group by TMSN3 and catalyzed by copper powder to obtain aminoflavonols in a facile manner.
The second part, was stereoselective synthesis of fluorocyclitols. Cyclitols are cyclohexanes containing three or more hydroxyl groups. Its bioactivity is attracted much attention by scientists. Some specific derivatives of cyclitols are used as antibiotics, anticancer drugs and antidiabetes.
The replacement of hydrogen atom(s) of cyclitols with fluorine atom(s) is considered to improves molecular permeability, chemical stability, promote bioactivities. We use D-(-)-quinic acid as starting material, partial of hydroxyl groups were appropriate protected. One of hydroxyl group is fluorinated by DAST, followed by OsO4/NMO for dihydroxylation. Based on the stereoselectivity of the reaction, fluorocyclitols with various stereochemistry were obtained.
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