Brønsted acidic ionic liquids promoted cyclocondensation reaction: Synthesis of 1,8-dioxo-octahydroxanthene (original) (raw)
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Journal of the Iranian Chemical Society, 2012
A simple, efficient, and environmentally benign route was developed for the preparation of 14-aryl or alkyl-14H-dibenzo[a,j]xanthene, 1,8-dioxo-octahydroxanthene and 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthene-11-ones from condensation of various aldehydes with (i) b-naphthol, (ii) cyclic 1,3-dicarbonyl compounds and (iii) b-naphthol and cyclic 1,3-dicarbonyl compounds, using novel polymeric catalyst [poly(AMPS-co-AA)] under solvent-free conditions. Use of easily available catalyst, shorter reaction times, better yields, simplicity of the reaction, heterogeneous system, and easy work-up are the advantages of the present method.
DABCO Catalyzed Synthesis of Xanthene Derivatives in Aqueous Media
2013
The reaction of 5,5-dimethylcyclohexane-1,3-dione with various heteroarylaldehydes afforded the corresponding heteroaryl substituted xanthene derivatives 1(a-f). The reaction proceeds via the initial Knoevenagel, subsequent Michael, and final heterocyclization reactions using 1,4-diazabicyclo[2.2.2]octane (DABCO) as a catalyst in aqueous media. The synthesized heteroaryl substituted xanthenes 1(a-f) reacted with malononitrile to obtain different alkylidenes 2(a-f). Short reaction time, environmentally friendly procedure, avoiding of cumbersome apparatus, and excellent yields are the main advantages of this procedure which makes it more economic than the other conventional methods.
Arabian Journal of Chemistry, 2012
ZrOCl 2 AE8H 2 O was found to be an efficient and recyclable catalyst for the reaction of aromatic aldehydes with dimedone to afford 1,8-dioxo-1,2,3,4,5,6,7,8-octahydroxanthenes under solvent-free conditions. Short reaction time, excellent yields and simple work-up are the advantages of this procedure. The interaction obtained from XRD studies was shown that the catalyst loses H 2 O during the reaction but it did not affect catalytic activity of the catalyst and the catalyst could be reused several times.
[DBN][HSO4]-Promoted Facile and Green Synthesis of Xanthene Derivatives via Knoevenagel Condensation
Der Pharmacia Lettre, 2021
A novel [DBN] [HSO 4 ] difunctionalized bronsted acidic ionic liquid-promoted Knoevenagel condensation followed by cyclization protocol has been developed for the first time by a successive reaction of aldehydes, and dimedone to afford xanthene derivatives in high to excellent yields at 80 ο C temperature. The ionic liquid provided the capability to allow a variability of functional groups, short reaction times, easy workup, high yields, recyclability of the catalyst and solvent-free conditions, thus providing economic and environmental advantages.