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To create your abstract, type over the instructions in the template box below. Fonts or abstract dimensions should not be changed or altered. • Compound 1 was obtained by basic hydrolysis of a CH 2 Cl 2 extract from S. lucida. • Were described the procedure to obtain and elucidate six oxidation products (2-7) from 1. • Compounds 2 , 3 , 5 and 7 are diosphenolic derivatives. • Compounds 4 and 6 experimented unexpected allylic oxidations and reductions. • Reaction mechanism to explain the allylic oxidations and reductions were proposed. The 7β,9α-dihydroxylongipin-2-en-1-one (1) was obtained by basic hydrolysis of a dichloromethane extract of the resinous exudate from aerial parts of Stevia lucida. The treatment of 1 with potassium permanganate in concentrated hydrochloric acid generated two diosphenolic derivatives (2 and 3) one of which showed an unexpected allylic oxidation (2). Diosphenol 3 was treated with Jones reagent yielding four oxidation products (4 - 7). Two of these (4 and 6) have structural changes that suggest a process of reduction of the enolic double bond of diosphenol and another process of allylic oxidation. To explain the formation of the compounds 4 and 6 a plausible reaction mechanism based on a sequence of isomerizations was proposed. The structures of (1 - 7) were established based on NMR (1D and 2D) data interpretation. [ABSTRACT FROM AUTHOR]

Graphical abstract To create your abstract, type over the instructions in the template box below. Fonts or abstract dimensions should not be changed or altered. Highlights • Austroeupatol (1) was obtained from Austroeupatorium inulifolium. • Three oxidation products were obtained from 1 and reaction mechanisms were proposed. • Bactericidal activity of all compounds was evaluated against four (4) bacterial strains. Abstract From aerial parts of Austroeupatorium inulifolium was obtained austroeupatol (1). The treatment of 1 with IBX generated the ketone 2 and keto-aldehyde 3. Due to the structural features of 1 , the hydroxy group corresponding to the primary alcohol (at C-19) is less reactive than the oxymethine hydroxy groups of the structure. The oxidative cleavage of 1 produced the hemiacetal 4 , since this reaction is quantitative and only this compound was detected, was proposed a reaction mechanism that involves the formation of a transition state that explain the generation of 4. The bactericidal activity of these oxidation derivatives was evaluated against four (4) bacterial strains [two Gram-positive (+) and two Gram-negative (-)]: Staphylococcus aureus , Enterococcus faecalis , Escherichia coli and Pseudomonas aeruginosa. [ABSTRACT FROM AUTHOR]