Nano Nickel-Cobalt Ferrite Catalysed One-Pot Multi-Component Synthesis of Xanthenediones and Acridinediones

A sustainable gateway to access 1,8-dioxo-octahydroxanthene scaffoldsviaa surface-engineered halloysite-based magnetically responsive catalyst

“…Also, a variety of catalysts, such as silica sulphuric acid, CaCl 2 , Fe 3+ −montmorillonite, and Zr(DP) 2 , have been employed for the synthesis of 1,8-dioxo-octahydroxanthene derivatives. 38–47 Though many of the aforesaid reported protocols have certain merits of their own, they still suffer from some intrinsic drawbacks, such as lesser yields, prolonged reaction times, high catalyst loading, use of toxic solvent, non-recyclability or expensive catalysts, or harsh reaction conditions. To overcome these issues, chemists are diverting their attention towards more facile and straightforward strategies that encompass a substantial decrease in reaction times, easy work-up and increased yields that match well with the goals of sustainable and green chemistry.…”

Zr(HSO4)4: Green, efficient and reusable catalyst for one-pot synthesis of 1,8-dioxooctahydroxanthene under solvent-free conditions

“…Xanthenes are also available from natural sources [6] . Many procedures are disclosed to synthesize xanthenes and benzoxanthenes such as montmorillonite K10 [7] , nano-ZnAl 2 O 4 [8] , sodium hydrogen sulfate [9] , cyclodehydrations [10] , [C 4 dabco][BF 4 ] ionic liquid [11] , Smcl 3 [12] , acid activated clay [13] , sulfonic acid functionalized silica [14] , template-containing Zn/MCM-41 [15] , Sulfamic acid [16] , Nickel-Cobalt Ferrite [17] , Many different methods have been reported for the synthesis of xanthenes; one of them is the condensation of aldehydes with cyclohexane-1,3-dione or 5,5-dimethylcyclohexane-1,3-dione to give 1,8-dioxooctahydroxanthene derivatives. This reaction has been conducted in the presence of strong protonic acids [18] , Lewis acids such as InCl 3 .4H 2 O [19] , FeCl 3 .6H 2 O [20] and heterogeneous catalysts like Dowex-50W [21] , NaHSO 4 .SiO 2 [22] , Ambertyst-15 [23] , HBF 4 /SiO 2 [24] and Sulfonic acid-functionalized LUS-1 [25] .…”