Abstract
A bitter principle, solidagonic acid, C_<22>H_<34>O_4, mp143-144℃, [α]_D-97.6°, was isolated from the root of Solidago altissima L.. The IR, UV and NMR spectral data and the chemical evidences suggested that solidagonic acid is an α,β-unsaturated carboxylic acid having an acetylated secondary hydroxyl group, two trisubstituted double bonds, two vinyl hydrogens, two vinyl methyl groups, one secondary methyl group and two tertiary methyl groups. The locations of the double bond and the acetoxyl group were determinde by introducing the methyl groups followed by dehydrogenations with Se or Pd-C. The structure of solidagonic acid was confirmed by the NMR spectrum of the derived saturated ketone (XIX). The ORD curves of some ketone derivatives (XIX, XXIV and XXX) led to the absolute configuration shown by (III) for solidagonic acid. Two other constituents, kolavenol((XXXIII), 3,5-dinitrobenzoate, C_<27>H_<36>O_6N_2, mp106℃) and kolavenic acid (methyl ester (XXV), C_<21>H_<34>O_2, bp151℃/1mmHg), were isolated. Their structures were deduced in connection with solidagonic acid.
