The new homogentisic acid derivatives miliusol (1b) and miliusolide (2) from Miliusa balansae were isolated and structurally determined by spectroscopic means. The relative configurations of the new 1b and its known acetate 1a were established. Furthermore, the symmetric ether bis(2-hydroxyphenyl)methyl ether 3, which was isolated for the first time from a natural source, the known flavonoids pachypodol and chrysosplenol C, and sodium benzoate were identified.
The leaves of Luvunga sarmentosa yielded two new apotirucallane triterpenoids, 3-epi-skimmiarepin A (1) and 21,23-epoxy-7alpha,21-dihydroxyapotirucalla-14,24-dien-3-one (2), and a new tirucallane triterpene, 3-epi-flindissol (3). Because of a hemiacetal functionality at C-21, all compounds occurred as mixtures of 21-epimers. 3-epi-Skimmiarepin A (1) and 3-epi-flindissol (3) were oxidized to the corresponding gamma-lactones. The structures have been elucidated on the basis of mass and NMR spectroscopic methods.
From the leaves of Xylopia vielana (Annonaceae) two dimeric guaianes named vielanins D and E were isolated and structurally elucidated by mass and NMR spectroscopy. Vielanin D and E consist of bridged ring systems formally representing the Diels-Alder products from the hypothetical guaiane-type monomers. Due to a hemiketal function at C-8' both compounds occurred as epimeric mixtures.
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