2723-56-0Relevant academic research and scientific papers
ALKALOIDS OF ALSTONIA ANGUSTIFOLIA
Ghedira, K.,Zechnes-Hanrot, M.,Richard, B.,Massiot, G.,Le Men-Olivier, L.,et al.
, p. 3955 - 3962 (1988)
Thirty-one alkaloids have been isolated from the leaves and from the stem bark of Alstonia angustifolia from Malaysia.Twenty of them were known compounds: yohimbine, O-acetyl yohimbine, pleiocarpamine, fluorocarpamine, cathafoline, cabucraline, N-1 desmethylquaternine, vincamajine, normacuisine B, lochnerine, affisine, akuammicine, 11-methoxyakuammicine, antrihine, alstonisine, alstoneine, alstophylline, macralstonine, villalstonine and tetrahydrocantleyine.Among the novel 11 alkaloids, three were monomers: 19,20-dehydro-10-methoxytalcarpime, 19,20-dehydro-O-acetyl yohimbine and hydroxystrictamine, and eight were dimers: villalstonine N-4'-oxide, 10-methoxy villalstonine, 10-methoxyvillalstonine N-4'-oxide, 10-methoxymacrocarpamine, 10-methoxymacrocarpamine N-4'-oxide, angusticraline, alstocraline an d foliacraline.Structural elucidation of the new alkaloids was based on spectral data analysis including high field 1H and 13C NMR.
Enantiospecific synthesis of (-)-alstonerine and (+)-macroline as well as a partial synthesis of (+)-villalstonine
Bi, Yingzhi,Zhang, Lin-Hua,Hamaker, Linda K.,Cook, James M.
, p. 9027 - 9041 (2007/10/02)
The enantiospecific synthesis of (-)-alstonerine (5) and (+)-macroline (8), as well as a partial synthesis of the Alstonia bisindole alkaloid villalstonine (2) has been completed. In addition, a more stable macroline equivalent 9 was prepared. The stereochemistry at C(15) and C(16) in 5 and 8 has been successfully installed by a stereoselective Claisen rearrangement followed by stereospecific hydroboration-oxidation of the exocyclic methylene function at C-16. The E ring in alstonerine 5 was constructed by a regioselective cyclization followed by a novel Swern oxidation under modified conditions [(COCl)2/DMSO/CH2Cl2, -78°C to -10°C/1.5 h; Et3N], whereas the C(20)-C(21) enone system in macroline (8) was generated via a convenient one pot process from the β-diol 45. Condensation of either synthetic (+)-macroline (8) or the macroline equivalent 9 with natural pleiocarpamine 7 in 0.2 N HCl furnished the antiamoebic, antimalarial bisindole alkaloid villalstonine 2. This constitutes the first partial synthesis of any of the Alstonia bisindoles from a synthetically derived indole moiety.
