Structural studies of polyhydroxybis(tetrahydrofuran)acetogenins from Annona squamosa using the combination of chemical derivatization and precursor-ion scanning mass spectrometry
✍ Scribed by Kazuo Hirayama; Satoko Akashi; Reiko Yuji; Uno Niitsu; Yoshinori Fujimoto
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 612 KB
- Volume
- 28
- Category
- Article
- ISSN
- 1076-5174
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
The structure of squamocin polyhydroxybis(tetrahydrofuran)acetogenin from Annona squamosa L., was characterized by a combination of the chemical derivatization and precursor‐ion scanning mass spectrometry. The lactone part of squamocin was modified with N,N‐dimethylethylenediamine in the vapour phase to afford a strong positive charge at one end of the skeleton. The derivative was ionized by fast atom bombardment (FAB), and the product ion spectrum from [M + H]^+^ and the precursor ion spectrum from the m/z 72 ion [CH~2~CHN^+^H(CH~3~)~2~] generated by low‐energy collision were acquired. The structure of the derivative could be characterized by the precursor‐ion spetrum from the m/z 72 ion, but little structural information could be obtained from the production spectrum from [M + H]^+^ of the derivative. By the attachment of a tertiary amino group to one end of the skeleton, charge‐remote fragmentation was facilitated and abundant and unique fragment ions were observed in the precursor‐ion spectrum. Structural characterization of six other isolated compounds was also carried out, and two novel compounds were found by this technique. A similar derivatization was applied in the peptide leu‐enkephalin, and full sequencing from the C‐terminus using precursor‐ion scanning from m/z 72 could be achieved.