| Summary: | 碩士 === 國立彰化師範大學 === 化學系 === 95 === Abstract
Coumestan and benzofuran are the common structures of natural products, which exhibiting a variety of pharmacological profile. We expect to develop synthetic strategies in order to synthesize in natural product of the similar skeleton. The article will be divided into two parts to describe our results.
Astragalus was one of a folk herbal drug used extensively in the Chinese. Hedysarimcoumestans A-H were first isolated from the extract of Hedysarum multijugum in 2006. They had quite common coumestans centre structure in natural product. On the biological activation, the extract from the roots had showed to improved the learning ability and remarkable acetylcholinesterase (AChE). On the synthetic strategies of hedysarim- coumestans could start with organostannane 12 and organohalide 13, which had the coumarin structure. Nature product of hedysarimcoumestan A (1)、B (2) and 1,3,9-Trimethoxy coumestan (9) also appeared smoothly synthetically via Stille coupling and intramolecule cyclization.
The lithospermic acid (14) was isolated from the roots of Lithospermum ruderale (Dougl. ex Lehm.),1 which was used in folk medicine for the treatment of macula, variola and constipation. In addition, Huang et al. had reported that lithospermic acid 14 could act as a potential agent against HIV-1 integrase activity and it’s a water-soluble compound. Lithospermic acid 14 could be visualized as the trimer of cinnamic acid. Thus, our synthetic strategies would be started with readily available cinnamates 15 and 17 to get rosmarinic acids 16. Herein, we wanted to present that lithospermic acid was employed by the sequences of Stille coupling reaction and Michael addition.
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