Eremophilane Sesquiterpenes from Ligularia myriocephala

Abstract

Five new eremophilenolides, 1β-angeloyloxy-6β,10β-dihydroxy-8β-methoxyeremophil-7(11)-en-8α,12-olide (1), 1β-angeloyloxy-6β,10α-dihydroxy-8α-methoxyeremophil-7(11)-en-8β,12-olide (2), 1β,6β-diangeloyloxy-8β,10β-dihydroxyeremophil-(11)-en-8α,12-olide (3), 1β,6β-diangeloyloxy-8α,10 α-dihydroxyeremophil-7(11)-en-8β,12-olide (4), 1β-angeloyloxy-8-oxoeremophil-6,9-dien-12-oic acid methyl ester (5) and one known compound, 8β,10β-dihydroxyeremophilenolide (6) were isolated from the extract of the whole plant of Ligularia myriocephala Ling. Their structures and stereochemistry were elucidated by various spectroscopic methods including intensive 2D-NMR techniques (COSY, gHMQC, gHMBC and ¹H-¹H NOESY) and HR-ESI-MS. A single-crystal X-ray experiment was performed for compound 1.

Key words

Ligularia myriocephala Ling - Compositae - sesquiterpenes - eremophilanolide

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