Eremophilane sesquiterpenes from Ligularia myriocephala.

Five new eremophilenolides, 1beta-angeloyloxy-6beta,10beta-dihydroxy-8beta-methoxyeremophil-7(11)-en-8alpha,12-olide ( 1), 1beta-angeloyloxy-6beta,10alpha-dihydroxy-8alpha-methoxyeremophil-7(11)-en-8beta,12-olide ( 2), 1beta,6beta-diangeloyloxy-8beta,10beta-dihydroxyeremophil-(11)-en-8alpha,12-olide ( 3), 1beta,6beta-diangeloyloxy-8alpha,10 alpha-dihydroxyeremophil-7(11)-en-8beta,12-olide ( 4), 1beta-angeloyloxy-8-oxoeremophil-6,9-dien-12-oic acid methyl ester ( 5) and one known compound, 8beta,10beta-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 (1)H- (1)H NOESY) and HR-ESI-MS. A single-crystal X-ray experiment was performed for compound 1.