- Divergent Synthesis of Solanidine and 22-epi-Solanidine
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A divergent synthesis of solanidine and 22-epi-solanidine, two 25S natural steroidal alkaloids, from 25R-configured diosgenin acetate, is described. Initially, solanidine was synthesized through a series of transformations including a cascade ring-switching process of furostan-26-acid, an epimerization of C25 controlled by the conformation of six-membered lactone ring, an intramolecular Schmidt reaction, and an imine reduction/intramolecular aminolysis process. To address the epimerization issue during Schmidt reaction, an improved synthesis was developed, which also led to a synthesis of 22-epi-solanidine. In this synthesis, selective transformation of azido lactone to azido diol and amino diol was realized through a reduction relay tactic. The azido diol was transformed to solanidine via an intramolecular Schmidt reaction/N-alkylation/reduction process and to 22-epi-solanidine via an intramolecular double N-alkylation process.
- Hou, Ling-Li,Shi, Yong,Zhang, Zhi-Dan,Wu, Jing-Jing,Yang, Qing-Xiong,Tian, Wei-Sheng
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- Asymmetric synthesis of (-)-solanidine and (-)-tomatidenol
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A concise asymmetric synthesis of two naturally occurring seco-type cholestane alkaloids (-)-solanidine and (-)-tomatidenol from (-)-diosgenin with a linear reaction sequence of 12 steps and 13 steps, respectively, is reported. The synthetic strategy includes the highly controlled establishment of highly functionalized octahydroindolizine ((-)-solanidine) and 1-oxa-6-azaspiro[4.5]decane ((-)-tomatidenol) cores with five stereocenters, respectively, from (-)-diosgenin, featuring two stereoselective cascade transformations including a modified cascade ring-switching process of furostan-26-acid to open the E-ring of (-)-diosgenin and a cascade azide reduction/intramolecular reductive amination to close the E- and F-rings of (-)-solanidine and (-)-tomatidenol. This work should enable further explorations of chemical and biological spaces based on solanidine, tomatidenol and related natural products.
- Chen, Fen-Er,Huang, Guanxin,Shi, Yong,Tian, Wei-Sheng,Wang, Yun,Zhuang, Chunlin
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- Synthesis of Demissidine and Solanidine
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Demissidine and solanidine, two steroidal alkaloids, are synthesized in eight steps from tigogenin acetate and diosgenin acetate, respectively, which involve the replacement of three C-O bonds with C-N bonds. Key transformations include a cascade ring-switching process of furostan-26-acid, an epimerization of C25, an intramolecular Schmidt reaction, and an imine reduction/intramolecular aminolysis process.
- Zhang, Zhi-Dan,Shi, Yong,Wu, Jing-Jing,Lin, Jing-Rong,Tian, Wei-Sheng
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p. 3038 - 3040
(2016/07/06)
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- Metabolism of the potato saponins α-chaconine and α-solanine by Gibberella pilicaris
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Potato tubers accumulate varying amounts of several saponins preferentially in the peel. These compounds are toxic to living cells containing sterols in their plasma membrane and are therefore thought to be preformed chemical defence compounds. Two strains of the potato pathogen Gibberella pulicaris (Fusarium sambucinum), R-6380 and R-7843, were analysed for their ability to metabolize the most predominant saponins found in tubers, α-chaconine and α-solanine. The first compound is degraded by both strains via removal of α-1,2-L-rhamnose leading to β2-chaconine. This product is converted to the aglycone, solanidine, which is further metabolized to unknown products. The release of α-1,2-L-rhamnose is also the first step in the break down of α-solanine by strain R-6380, followed by the removal of the β-1,3-bound glucose molecule leading to γ-solanine, which is not metabolized any further. Strain R-7843 is not able to metabolize α- solanine. Crude protein extracts of the culture fluid of both strains contained enzymes able to convert α-chaconine to β2-chaconine, but with no α-solanine metabolic activity. This result indicates that G. pulicaris excretes enzymes specific for different saponins.
- Weltring, Klaus-M,Wessels, Judith,Geyer, Rudolf
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p. 1005 - 1009
(2007/10/03)
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- Thermal Degradation of Glycosides, V - Hydrothermolysis of Triterpenoid and Steroid Glycosides
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In this paper the hydrothermolysis of triterpenoid and steroid glycosides is described.By mere heating with water or water/1,4-dioxane solution, the triterpenoid and steroid glycosides 1, 4 and 15, 16, 25, 29, respectively, are converted into their aglycones and prosapogenins.Furthermore, hydrothermolysis of the triterpenoid 3,28-O-bisglycosides 5, 6, 8, 9, 12 affords the corresponding 3-O-glycosides and reduced oligosaccharides formed by selective cleavage of the ester glycosidic linkage.It is expected that this hydrothermolysis is useful for the structure determination of some triterpenoid and steroid glycosides and for yielding new oligosaccharides.The hydrothermolyzed products have been isolated by chromatography and their structures elucidated by spectroscopic methods.Key Words: Degradation, thermal / Thermolysis / Glycosides / Carbohydrates / Triterpenoids / Steroids
- Kim, Youn Chul,Higuchi, Ryuichi,Komori, Tetsuya
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p. 453 - 460
(2007/10/02)
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- ALKALOIDS OF Rhinopetalum stenantherum. II. THE STRUCTURE OF STENANTHINE AND STENANTHIDINE
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From a methanolic extract of the epigeal part of Rhinopetalum stenantherum have been isolated β-chaconine (I) and the new glucoalkaloids stenanthine with mp 262-264 deg C, D 46.5 deg, C45H73NO13 (II), and stenanthidine with mp 269-271 deg C, D -47.5 deg, C39H63NO11 (III).On the basis of the facts that partial hydrolysis of trioside (II) formed the biosides (I) and (III), and that on the hydrolysis of the latter the monoside γ-chaconine was found, it may be assumed that stenanthine has the structure of solanidine 3-O-(--D-glucoside), and stenanthidine that of solanidine 3-O-.
- Samikov, K.,Rashkes, Ya. V.,Shakirov, R.,Yunusov, S. Yu.
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p. 273 - 278
(2007/10/02)
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