RESUMO
The series of naturally occurring furanonaphthoquinones is extended by identification of the derivatives 2-(1'-methylethenyl)-5-hydroxynaphtho[2,3-b]furan-4,9-dione and 2-(1'-methylethenyl)-7-hydroxynaphtho[2,3-b]furan-4,9-dione. They are accompanied in the stem barks of Newbouldia laevis by the known analogues 5-hydroxy-dehydro-iso-alpha-lapachone, 2-acetyl-5-hydroxynaphtho[2,3-b]furan-4,9-dione and 2-(1'-methylethenyl)naphtho[2,3-b]furan-4,9-dione along with the rare atraric acid and the new 2-(1'-methylethenyl)-6-hydroxy-2,3-dihydrobenzofuran. The structures of these compounds were established from spectroscopic studies.
Assuntos
Benzofuranos/isolamento & purificação , Bignoniaceae/química , Furanos/isolamento & purificação , Hidroxibenzoatos/isolamento & purificação , Naftoquinonas/isolamento & purificação , Casca de Planta/química , Benzofuranos/química , Furanos/química , Hidroxibenzoatos/química , Naftoquinonas/química , Ressonância Magnética Nuclear Biomolecular , Caules de Planta/química , Espectrometria de Massas por Ionização por Electrospray/métodosRESUMO
Twenty-three cationic chiral analytes were resolved in capillary electrophoresis using native beta-cyclodextrin and single isomer heptakis-(2-O-methyl-3,6-di-O-sulfo)-beta-cyclodextrin as chiral selectors. For 12 of 16 chiral analytes resolved with both chiral selectors the enantiomer migration order was opposite. In selected cases the structure of cyclodextrin-analyte complexes in aqueous solution was investigated using one-dimensional transverse rotating frame nuclear Overhauser and exchange spectroscopy. It was found that in contrast to mainly inclusion-type complexes between chiral analytes and beta-cyclodextrin, external complexes are formed between the chiral analytes and structurally crowded, highly charged heptakis-(2-O-methyl-3,6-di-O-sulfo)-beta-cyclodextrin.
Assuntos
Ciclodextrinas/química , Eletroforese Capilar/métodos , beta-Ciclodextrinas , Compostos Heterocíclicos/isolamento & purificação , Indicadores e Reagentes/química , Espectroscopia de Ressonância Magnética , Análise Espectral , EstereoisomerismoRESUMO
Ateleia glazioviana Baillon, Leguminosae-Papilionoideae, árvore de ocorrência na regiäo de Palmeira das Missöes (RS), possui atividade tóxica para o gado, ictiotóxica e repelente de insetos, referida por populares do interior do estado. Do extrato de sementes e pericarpo alado, foram isolados três aminoácidos näo protéicos, dois dos quais identificados como ácido 1-aminociclobutano -1,3-dicarboxílico e Ð-acetilomitina
