Lignans, flavonoids and coumarins from <i>Viola philippica</i> and their α-glucosidase and HCV protease inhibitory activities

<p>Two lignans including a new one, five flavonoids and five coumarins were isolated from the whole plant of <i>Viola philippica</i> (synonymised as <i>Viola yedoensis</i> Makino). The new compound was structurally determined as (7<i>R</i>,8<i>S</i>,8′<i>S</i>) -3,3′-dimethoxy- 4,4′,9-trihydroxy- 7,9′-epoxy-8,8′-lignan 9-O-rutinoside by analysis of its NMR, MS and CD spectroscopic data. The known compounds were characterised by comparing their NMR and MS data with those reported. Among the known compounds, 5-hydroxy-4′-methoxyflavone-7-O- rutinoside, 6,7-di-O-β-D- glucopyranosylesculetin, and 7<i>R</i>,8<i>S</i>-dihydrodehydrodiconiferyl alcohol 4-O-β-D- glucopyranoside were isolated and identified from this genus for the first time. Of these compounds, 5-hydroxy-4′-methoxyflavone-7-O-rutinoside and (7<i>R</i>,8<i>S</i>,8′<i>S</i>) -3,3′-dimethoxy- 4,4′,9-trihydroxy- 7,9′-epoxy-8,8′-lignan 9-O-rutinoside were potently active against α-glucosidase, while the two dimeric coumarins, 5, 5′-bi (6, 7-dihydroxycoumarin) and 6,6′,7,7′-tetrahydroxy-5,8′-bicoumarin potently inhibited HCV protease.</p

Syntheses, Structures, and Magnetic and Luminescence Properties of a New Dy^III-Based Single-Ion Magnet

Three new Ln^III complexes based on 2,2′-bipyridine [Ln­(hfac)₃(bpy)] (Ln = Dy (<b>1</b>), Tb (<b>2</b>), or Ho (<b>3</b>); hfac = hexafluoroacetylacetonate; and bpy = 2,2′-bipyridine) have been synthesized and characterized structurally and magnetically. Single-crystal X-ray analysis shows that all these complexes contain one [Ln­(hfac)₃(bpy)] unit in which a center Ln^III ion is surrounded with a slightly distorted square-antiprismatic LnO₆N₂ coordination sphere formed by three bischelate hfac anions and one bpy ligand. Both static and dynamic magnetic properties were studied for complex <b>1</b>, which is proved to be a new single-ion magnet. The luminescence characterizations of complexes <b>1</b> and <b>2</b> are also studied in this paper

Syntheses, Structures, and Magnetic and Luminescence Properties of a New Dy^III-Based Single-Ion Magnet

Three new Ln^III complexes based on 2,2′-bipyridine [Ln­(hfac)₃(bpy)] (Ln = Dy (<b>1</b>), Tb (<b>2</b>), or Ho (<b>3</b>); hfac = hexafluoroacetylacetonate; and bpy = 2,2′-bipyridine) have been synthesized and characterized structurally and magnetically. Single-crystal X-ray analysis shows that all these complexes contain one [Ln­(hfac)₃(bpy)] unit in which a center Ln^III ion is surrounded with a slightly distorted square-antiprismatic LnO₆N₂ coordination sphere formed by three bischelate hfac anions and one bpy ligand. Both static and dynamic magnetic properties were studied for complex <b>1</b>, which is proved to be a new single-ion magnet. The luminescence characterizations of complexes <b>1</b> and <b>2</b> are also studied in this paper