| 1. Total Synthesis of Pariphyllin BPariphyllin B was isolated from Paris polyphylla. It shows antibiosis and anti-tumor activities. For it’s a kind of Derride Michael so the commercial available triterpenoidal saponins Diosgenins was used as Oleandrigenin. Then we Link the monosaccharide building one by one,after globle deprotection accomplished the first total synthesis of Pariphyllin. The synthesis spends overall 24 steps and 14.4% yield with a convergent linear sequence of only 16 steps. 2. Synthesis of Starfish Saponin Goniopectenoside B derivativesGoniopectenoside B, together with goniopectenoside A and C, was isolated from Goniopecten demonstrans.The first total Synthesis of Starfish Saponin Goniopecteno side B belong to Doctor Guozhi Xiao, Yu lab. The cholestane aglycon was prepared by the repetr manner. Four oligosaccharide derivative was assembled from some monosaccharide building blocks in an efficient and straightforward manner. After globle deprotection of protection groups accomplished the total synthesis of Starfish Saponin Goniopectenoside B four oligosaccharide derivative. 3. Synthetic Study of Starfish Saponins: Pectinioside EPectinioside E was isolated from Asterina Pectinifera in 1988 by Sasak I。According to report this molecule shows protent antitumor activities. Along with the Goniopectenoside B, Pectinioside E also covers a Δ9(11)-3β,6α-dihydroxysteroidal core structure, however, comparing with the former, Pectinioside E contains a β-OH ketone side chain. As we all know this structure is sensitive to base and acid. We try to protecting the ketone by 1,3-propanedithiol but we faild to find the condition of deprotection; Also we want to reduction the ketone, however the oxidation of the secondary alcohol still stands there. In the view of diffculties in the construct the β-OH ketone side chain, we proposed a new synthetic strategy. The acidity of the α-H lead to the re-aldo reaction, replacing it mayl be a good manner. This part of work is still in progress. |
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