β-Phenylselenoalanine as a dehydroalanine precursor–efficient synthesis of alternariolide (AM-toxin I)
摘要:
Alternariolide (AM-toxin) is synthesized in 44% overall yield from L-2-amino-5-(4-methoxyphenyl)pentanoic acid; D-beta-phenylselenoalanine is used as the dehydroalanine precursor.
The cyclic depsipeptides, AM-toxins I and II and AM-toxin I analogs, were efficiently and rapidly prepared by the Fmoc-based solid-phase method for the synthesis of linear depsipeptides, with N-[(dimethylamino)-1H-1,2,3-triazolo[4,5-b]pyridin-1-ylmethylene]-N-methylmethanaminium hexafluorophosphate N-oxide (HATU) being used for their subsequent cyclization.
Alternariolide (AM-toxin) is synthesized in 44% overall yield from L-2-amino-5-(4-methoxyphenyl)pentanoic acid; D-beta-phenylselenoalanine is used as the dehydroalanine precursor.
Mass spectrometry ofAlternaria mali toxins and related cyclodepsipeptides
The structures of AM-toxins I, II and III, host specific phytotoxic metabolites of Alternaria mali, can be readily deduced from low and high resolution mass spectral data, since the amino acids and their sequences are demonstrated by this technique. Additionally, the general fragmentation of these compounds by electron impact is discussed by comparing the spectra of analogous synthetic compounds.