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|Title: ||Indole alkaloids from Neisosperma Oppositifolia and kopsia Singapurensis; Acetamidostilbene radical cation oxidative cyclization approaches to unusual Indolostilbene hybrids|
|Authors: ||Kartini Ahmad|
|Keywords: ||Indole alkaloids|
|Issue Date: ||May-2009 |
|Publisher: ||University Malaya|
|Abstract: ||The phytochemical study on Apocynaeae family (Neisosperma oppositifolia and Kopsia
singapurensis) involves extraction, separations by using various chromatographic methods and structural determination by spectroscopic techniques such as UV, IR, NMR including 1D-NMR (1H, 13C, and DEPT), 2D-NMR (COSY, NOESY, HMQC/HSQC, and HMBC)and MS (LCMS and HRESIMS). The structures of the compounds were also elucidated by comparison with previous work.
Isolation studies on the bark of Neisosperma oppositifolia yielded oppositinine A 356,
oppositinine B 357, isoreserpiline 90, isocarapanaubine 108, vobasine 358, 10-
methoxydihydrocorynantheol-N-oxide 359 and ochropposinine oxindole 360. Oppositinine
A 356 and oppositinine B 357 are new -carboline alkaloid and the others are known indole alkaloids.
Eleven compounds were successfully isolated from the bark of Kopsia singapurensis of
which one is a new indole alkaloid aspidofractinine type); namely 15-hydroxykopsinine-Noxide 364. The known compounds are venalstonine 163, venacarpine A 222, rhazinilam 3,pleiocarpamine 164, 16-epi-deacetylakuammiline 126, 15-hydroxykopsinine 361, 16- hydroxymethylpleiocarpamine 207, lonicerine 225, kopsinine-N-oxide 362 and 16-epideacetylakuammiline- N-oxide 363.
Further investigation on the leaves of the same plant afforded three compounds. The
compounds are singaporentine A 365, kopsifoline A 227 and kopsininic acid 240.
Singaporentine A 365 is a new compound belonging to a rare type of indole alkaloid. At present, only six alkaloids possess this peculiar skeleton; kopsifoline A-F previously
isolated from Kopsia fruticosa.
In a parallel investigation, new methods for the construction of indoles, indolines and
bisindolines bearing C-2 aryl substituents are described in this thesis.|
|Description: ||Thesis (PhD) -- Faculty of Science, University of Malaya, 2009.|
|Appears in Collections:||PhD Theses : Science|