Oncinotine-Type Spermidine Alkaloids from Oncinotis tenuiloba. Transformation of N-acetyloncinotin-12-one to N,N′-diacetylinandenin-12-one
✍ Scribed by Martin K.-H. Doll; Armin Guggisberg; Manfred Hesse
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- German
- Weight
- 636 KB
- Volume
- 79
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
From extracts of Oncinotis tenuiloba STAPF, two novel polyamine alkaloids, oncinotin-1 1-one (5) and oncinotin-12-one (6), were isolated. Peracetylation of 6 provided the N-acetyl derivative 11 as well as N,N'-diacetylinandenin-10-en-12-one (12) due to ab-elimination-type side reaction resulting in ring enlargement of 11 (Sclzeme 1). Deuteration of 12 yielded 13, showing the same retention time as N,N'-diacetylinandenin-12-one (14), when co-HPLC was performed together with different keto-isomeric N,N'-diacetylinandeninones. Structure elucidation was extended by Schmidt degradation of 6 and N,N'-diacetyl(l0,l l-2H2)inandenin-12-one (13); the degradation products were identified by GC and ESI-MS. The structure of 5 was proposed on the basis of spectroscopic means. Comparison of the spectroscopic data of 5 with those obtained from synthetic material as well as co-HPLC of the N-acetyl derivative 20 together with the corresponding synthetic compound revealed the identity of the substances and confirmed the structure of 5. Additionally, oncinotine (2) and neooncinotine (3) were isolated, separated, and identified with authentic samples by co-HPLC of their N-acetyl derivatives 8 and 9, respectively. ') Atom numberings and names used in the text and Schemes are in accordance with earlier publications; for systematic names, eJ Exper. Part and references given for the compounds.