STRUCTURAL STUDIES OF POLYHYDROXYBIS(TETRAHYDROFURAN)ACETOGENINS FROMANNONA-SQUAMOSA USING THE COMBINATION OF CHEMICAL DERIVATIZATION AND PRECURSOR-ION SCANNING MASS-SPECTROMETRY
K. Hirayama et al., STRUCTURAL STUDIES OF POLYHYDROXYBIS(TETRAHYDROFURAN)ACETOGENINS FROMANNONA-SQUAMOSA USING THE COMBINATION OF CHEMICAL DERIVATIZATION AND PRECURSOR-ION SCANNING MASS-SPECTROMETRY, Organic mass spectrometry, 28(12), 1993, pp. 1516-1524
The structure of squamocin polyhydroxybis(tetrahydrofuran)acetogenin f
rom Annona squamosa L., was characterized by a combination of the chem
ical derivatization and precursor-ion scanning mass spectrometry. The
lactone part of squamocin was modified with NN-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 production spectrum from [M + H]+ and the precursor ion spe
ctrum from the m/z 72 ion [CH2-CHN+H(CH3)2] generated by low-energy co
llision were acquired, The structure of the derivative could be charac
terized by the precursor-ion spectrum 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 fac
ilitated and abundant and unique fragment ions were observed im the pr
ecursor-ion spectrum. Structural characterization of six other isolate
d compounds was also carried out, and two novel compounds were found b
y this technique. A similar derivatization was applied in the peptide
leu-enkephalin, and full sequencing from the C-terminus using precurso
r-ion scanning from m/z 72 could be achieved.