- Stereoselective introduction of oxygen functionalities at the 11β- position of erythrinan skeleton: Total syntheses of (±)-erythristemine and (+)-erythrartine
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Oxidation of 8-oxoerythrinan and 8-oxo-1,7-cycloerythrinan derivatives with 2 mol eq of ceric ammonium nitrate in alcohols or acetic acid gave the corresponding 11β-alkoxy or acetoxy compounds in moderate yield. Thus, (±)- 3,3,15,16-tetramethoxy-1,7-cycloerythrinan-2,8-dione and (+)-erysotramidine gave the corresponding 11β-methoxy and 11β-acetoxy derivatives on oxidation in methanol and in acetic acid, respectively. Those compounds were respectively converted into (±)-erythristemine and (+)-erythrartine in several steps, thus achieving the total synthesis of these alkaloids.
- Isobe,Mohri,Takeda,Suzuki,Hosoi,Tsuda
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p. 197 - 203
(2007/10/02)
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- SYNTHESIS OF 11β-HYDROXY ERYTHRINA ALKALOID, ERYTHRARTINE, AND ITS O-ACETATE (ERYTHRASCINE?)
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Oxidation of an erythrinan alkaloid erysotramidine (4) with CAN in AcOH-MeCN gave, in moderate yield, the 11β-acetoxy derivative (5b), which was transformed into erythrartine (8).Its O-acetate (O-acetylerythrartine) was not identical with erythrascine in the 1H-nmr spectra, presenting an ambiguity on the reported structure of erythrascine.
- Isobe, Kimiaki,Mohri, Kunihiko,Suzuki, Kazumi,Haruna, Mitumasa,Ito, Kazuo,et al.
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p. 1195 - 1198
(2007/10/02)
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