Catea ternifolia var. calyculata yielded the new sesquiterpene lactones 9a-acetoxyzexbrevin (1) and 9a-hydroxy-l 1,13-dihydro-l la, 13-epoxy at npliciolide-80-0-[2-methylacrylate] (4). Their structures were characterized by nmr and mass spectral methods and the molecular structure of the latter compound was determined by single crystal x-ray diffraction.Calca ternifolia var. ternifolia contained a mixture of two known calein-type compounds as well as a crystalline mixture of the known 9a-hydroxy-l 1,13-dihydro-atripliciolide-8/S-0-[2-methylacrylate] (3) and 9o-hydroxy-l 1,13-dihydro-l , 13-epoxyatripliciolide-8^-0-[2-methylacrylate] (4). Single crystal x-ray data of a mixture of 3 and 4 were obtained.
The isolation and structure determination of a new eudesmanolide, irazunolide (1), from Hieracium irazuensis is reported. The structure was inferred from nmr and mass spectral data, and the molecular structure of irazunolide was determined by single crystal X-ray diffraction.Because of the limited data on the chemistry of the tribe Lactuceae (Cichorieae) of the family Compositae (1), we wished to learn about the chemical constituents
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