Complete assignments of NMR data and assessment of trypanocidal activity of new eremantholide C derivatives

English. Chemical transformations of eremantholide C (1), a sesquiterpene lactone that was isolated from Lychnophora trichocarpha Spreng. led to five new derivatives: 1′,2′- epoxyeremantholide C (2), 5-n-propylamine-4,5-dihydro-1′,2′-epoxyeremantholide C (3), 5-n-propylammonium-4,5-dihydro-1′,2′-epoxyeremantholide C chloride (4), 5-n-propylammonium-4,5-dihydroeremantolide C chloride (5) and 16-O-ethyleremantholide C (6). The structures of all these derivatives were assigned on the basis of IR, MS, 1H and 13C NMR data by 1D and 2D techniques. Eremantholide C and the derivatives 2, 4 and 5 were evaluated against trypomastigotes Y and CL strains of Trypanosoma cruzi. Eremantholide C completely inhibited the growth of both the parasites strains while all derivatives were partially active against the CL strain and inactive against the Y strain.

Portuguese. Transformações químicas realizadas em eremantolida C (1), uma lactona sesquiterpênica isolada de Lychnophora trichocarpha Spreng. originaram cinco novos derivados: 1′,2′-epoxieremantolida C (2), 5-n-propilamino-4,5-diidro-1′,2′-epoxieremantolida C (3), cloreto de 5-n-propilamônio-4,5-diidro-1′, 2′-epoxieremantolida C (4), cloreto de 5-n-propilamônio-4,5-diidroeremantolida C (5) e 16-O-etileremantolida C (6). As estruturas químicas de todos estes derivados foram elucidadas com base nos espectros de IV, EM, RMN de 1H e de 13C e por meio de técnicas 1D e 2D. Eremantolida C e os derivados 2, 4 e 5 foram avaliados frente a cepas tripomastigotas Y e CL de Trypanosoma cruzi. Eremantolida C inibiu completamente o crescimento de ambas as cepas de parasitas, enquanto todos os derivados foram parcialmente ativos contra a cepa CL e inativos contra a cepa Y.