Cyanogenic and non-cyanogenic pyridone glucosides from Acalypha indica (Euphorbiaceae)
2009; Elsevier BV; Volume: 70; Issue: 2 Linguagem: Inglês
10.1016/j.phytochem.2008.12.011
ISSN1873-3700
AutoresMonika Hungeling, Matthias Lechtenberg, Frank R. Fronczek, Adolf Nahrstedt,
Tópico(s)Chemical synthesis and alkaloids
ResumoSeven cyanopyridone derivatives and one corresponding seco compound have been isolated from a methanolic extract of the inflorescences and leaves of Acalypha indica L. (Euphorbiaceae). The absolute configuration of the main cyanogenic glucoside acalyphin, (-)-(5R,6S)-5-cyano-5-beta-d-glucopyranosyloxy-6-hydroxy-4-methoxy-1-methyl-2(5,6-dihydro)-pyridone, was deduced from an X-ray crystallographic study. In addition, the 6R-epimer of acalyphin, epiacalyphin, and the corresponding pair of N-demethyl derivatives were isolated. The corresponding amide of acalyphin and a 1',2'-glucosyl-fused epiacalyphin amide were isolated from air-dried material. Structural elucidation was performed by means of (1)H and (13)C NMR-spectra, chiroptical methods such as CD-spectroscopy and optical rotation. Two further corresponding derivatives, an aromatized compound and an open-chain structure, were isolated from the aqueous phase.
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