Topic
Xanthene
About: Xanthene is a research topic. Over the lifetime, 2132 publications have been published within this topic receiving 34803 citations. The topic is also known as: Xanthene & dibenzo[a,e]pyran.
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TL;DR: In this paper, double cyclization of aryloxy-phenyl acetamides is promoted by oxalyl chloride/stannyl chloride and gives 3,4-dioxocularine and aristocularine alkaloids.
Abstract: Double cyclization of aryloxy-phenyl acetamides is promoted by oxalyl chloride/stannyl chloride and gives 3,4-dioxocularine and aristocularine alkaloids. Rearrangement of the dibenzoxepine ring prior to the second cyclization produces xanthene derivatives. The synthesized cularinoids exhibit significant activity against various tumoral cell lines.
17 citations
TL;DR: In this paper, the dissociation constants of fluorescein halo derivatives containing substituents in the xanthene ring and/or in the phthalic acid moiety were determined in 91.4 wt % aqueous ethanol.
Abstract: The dissociation constants of fluorescein halo derivatives containing substituents in the xanthene ring and/or in the phthalic acid moiety were determined in 91.4 wt % aqueous ethanol. The tautomerism of the dyes was inferred from the electronic absorption spectra of ions and molecules in this solvent and of the dichloromethane and chloroform extracts of associates of the anions with tetra-n-butylammonium cations. The equilibria in two-phase systems were considered.
17 citations
TL;DR: In recent years, xanthenes and benzoxanthens have been of great interest because they have been found to possess useful biological activities such as anti-inflammatory, 1 antiviral, 2 and antibact...
17 citations
TL;DR: In this article, various xanthene derivatives have been prepared efficiently through a simple method using choline chloride/tin(II) chloride (ChCl·2SnCl2) deep eutectic solvent (DES), alone, or in the presence of Fe3O4/ƛ-carrageenan/Zn(II), magnetic bionanocatalyst.
Abstract: In this study, various xanthene derivatives have prepared efficiently through a simple method using choline chloride/tin(II) chloride (ChCl·2SnCl2) deep eutectic solvent (DES), alone, or in the presence of Fe3O4/ƛ-carrageenan/Zn(II) magnetic bionanocatalyst. In the employed procedure, 2-naphthol derivatives have mixed with aromatic or aliphatic aldehydes and the reactions have been completed in the presence of DES at 90 °C in 1.5 h. In addition, using DES/Fe3O4/ƛ-carrageenan/Zn(II), the reaction time was reduced to 30 min. The employed DES has been recycled four times without important loss of its activity.
17 citations
TL;DR: In this paper, a series of metal chloride-based acidic ionic liquids have been prepared and used as an efficient catalyst in one-pot multicomponent synthesis of biscoumarins and substituted xanthenes derivatives under solvent-free conditions.
Abstract: A series of metal chloride-based acidic ionic liquids have been prepared and used as an efficient catalyst in one-pot multicomponent synthesis of biscoumarins and substituted xanthenes derivatives under solvent-free conditions. Among the acidic ionic liquids, N-methylpyrrolidonium zinc chloride (Hnmp/ZnCl3)-based Bronsted–Lewis acidic ionic liquids were found to be an effective and recyclable catalyst for a one-pot synthesis of biscoumarins through the domino Knoevenagel–Michael reaction of a variety of aldehydes with 4-hydroxycoumarin in short reaction times. The reactions which occur under relatively mild conditions afforded the biscoumarin derivatives employing a very low loading of catalyst in satisfactory isolated yields and high purity after simple work-up. The Bronsted–Lewis acidic ionic liquid catalyst was reused four times without any variation in yield.
17 citations