Ugonin S (1)及ugonin L (2)是由錫蘭七指蕨分離出來的天然物，錫蘭七指蕨為傳統中藥作為消炎解熱劑，ugonin S 及ugonin L的結構為flavone，並帶有一個cyclogeranyl取代於苯環上，ugonin S具有很強的抗發炎活性，ugonin L具有優異的抗氧化作用，由於天然物分離的量很少，且這兩個天然物到目前為止並未有合成之報導，為了進一步探討其他生物活性，所以引發我們的興趣，建立一個有效的合成方式來合成ugonin S 及ugonin L。
在本論文中，有效的合成方法已建立起來合成ugonin S 及ugonin L，從cyclogeranic acid為起始物開始經11個合成步驟，成功的合成了消旋的ugonin S 及ugonin L；另外，具絕對立體構型的ugonin L [(10S,11R)-2, (10R,11S)-2]也分別經10個合成步驟順利的合成出來，這些合成的化合物將於近期內評估其生物活性。
Ugonin S (1) and ugonin L (2) were isolated and characterized as two new flavonoids from the rhizomes of Helminthostachys zeylanica. The rhizomes of H. zeylanica is a Chinese herbal medicine used as an antipyretic and antiphlogistic agent. Ugonins S and ugonin L are two flavones with a cyclized geranyl substituent at C-6 position, and this group was further cyclized with vicinal hydroxyl group. Ugonin S showed anti-inflammatory effect and ugonin L was found to show anti-oxidative activity. Until now, the total synthesis of ugonin S and ugonin L was not reported yet, and their absolute stereochemistry were not determined. In order to obtain more material for further study the biological activities, the total synthesis of ugonin S and ugonin L. was investigated.
In this thesis, an efficient method to synthesize ugonin S and ugonin L was established. Starting from cyclogeranic acid, two racemic mixture of ugonin S (1) and ugonin L (2) were successfully synthesized in eleven steps. In addition, stereoselective synthesis of ugonin L [(10S,11R)-2, (10R,11S)-2] was also carried out in ten steps, respectively. The biological activity of synthesized compounds will be evaluated in the near future.
