Search

The magnetically separable heterogeneous nickel–zinc ferrite (NiZnFe2O4) catalyst was synthesized and used for the first time as an environmentally friendly reusable catalyst for the synthesis of 2-amino-4H-chromene derivatives via a one-pot, three-component condensation reaction of various salicylaldehydes and malononitrile or ethyl cyanoacetate with nitromethane or nitroethane in ethanol at room temperature. There have been no reports of nickel zinc ferrite being used as a catalyst. The catalyst was specified by using several techniques, including DSC–TGA, FT-IR, X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), BET, and scanning electron microscope (SEM). The present protocol suggests some benefits, which include green reaction conditions, simple reaction work-up, short reaction time, excellent product yields, chromatography-free purification, and high efficiency of the heterogeneous catalyst. More importantly, this catalyst was recovered from the reaction mixture using a simple external magnet, and it was reused successively at least seven times without any significant loss of catalytic activity. [ABSTRACT FROM AUTHOR]

A novel –SO3H difunctionalized Bronsted acidic ionic liquid (BAIL) 1, 5-bis (butanesulphonic acid)-diazobicyclo [4,3,0] non-5-enium hydrogen sulphate [BBSA-DBN][HSO4] is introduced for efficient synthesis of quinoxalines via condensation of substituted 1,2-diketones and various aromatic 1,2-diamines. It could serve as a dual functional catalyst for these reactions. This method has the advantages of mild reaction conditions, high yields, short reaction times, easy work-up, non-chromatographic separations and being environmentally friendly. This protocol provides an effective and environmentally friendly alternative methodology for production of quinoxalines and extends the chemical utilization of benzil in organic synthesis. This room-temperature-derived ionic liquid is highly acidic due to presence of two –SO3H groups and two HSO4− anions. Moreover, the IL [BBSA-DBN][HSO4] could be easily recovered and reused at least five times without change in its catalytic activity. The formation of IL [BBSA-DBN][HSO4] was confirmed by 1H, 13C NMR spectroscopic techniques. [ABSTRACT FROM AUTHOR]