- 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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- Synthesis of demissidine by a ring fragmentation 1,3-dipolar cycloaddition approach
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A synthesis of the steroidal alkaloid demissidine from epiandrosterone is reported. A ring fragmentation reaction that efficiently ruptured the D-ring of a diazo ester derivative of epiandrosterone to provide an aldehyde tethered ynoate product was key to this sequence. Incorporation of the indolizidine framework was achieved by an azomethine ylide 1,3-dipolar cycloaddition.
- Zhang, Zhe,Giampa, Geoffrey M.,Draghici, Cristian,Huang, Qiufeng,Brewer, Matthias
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p. 2100 - 2103
(2013/06/05)
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- Confirmation of Structure of Isosolacapine: Stereochemistry at Ring Juncture of Indolizidine Moiety of 22βH Solanidanes by 13C and 1H NMR Spectroscopy
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Isosolacapine, a minor steroidal alkaloid of Solanum pseudocapsicum, earlier assigned structure 3, possesses a novel 22β N stereochemistry in a 22,26-epiminocholestane skeleton.This alkaloid has now been isolated from Solanum capsicastrum and its structure confirmed by its conversion to solanogantamine (8), a 22αH solanidane derivative ex Solanum giganteum.The ring-juncture stereochemistry of the indolizidine moiety of 22β H solanidanes, in general, has been elucidated on 13C and 1H NMR spectral evidences.
- Chakravarty, Ajit K.,Pakrashi, Satyesh C.
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p. 311 - 313
(2007/10/02)
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