Magnetically recoverable and reusable CuFe₂O₄nanoparticle-catalyzed synthesis of benzoxazoles, benzothiazoles and benzimidazoles using dioxygen as oxidant

Abstract

A green and efficient strategy for the synthesis of benzoxazoles, benzothiazoles and benzimidazoles has been developed by using inexpensive, readily available, dioxygen-stable and recyclable CuFe2O4 as the nanocatalyst.

MIL‐101(Fe) hexagonal microspindle as a highly efficient, reusable and versatile catalyst for benzo‐fused heterocyclic nucleus synthesis

“…According to the literature, a possible mechanism for the condensation/cyclization synthesis of benzo‐fused heterocyclic nucleus derivatives using the heterogeneous MIL‐101(Fe) catalyst is proposed (Figure ). Initially, the aldehyde carbonyl group is activated by the Lewis acid sites of the heterogeneous MIL‐101(Fe) catalyst.…”

Magnetically Separable Transition Metal Ferrites: Versatile Heterogeneous Nano‐Catalysts for the Synthesis of Diverse Bioactive Heterocycles

“…Yang et al . (Table ) prepared a series of benzoxazoles ( 80 ) and benzothiazoles ( 80 a ) from the reactions of substituted benzaldehydes ( 1 ) and 2‐aminophenol ( 79 ) or 2‐aminothiophenol ( 79 a ) in the presence of a catalytic amount of magnetic nano‐CuFe 2 O 4 as an efficient, heterogeneous, reusable nano‐catalyst in toluene at 110 °C.…”

Recent Trends in the Synthesis of Benzimidazoles From o‐Phenylenediamine via Nanoparticles and Green Strategies Using Transition Metal Catalysts

“…Yang et al . reported the synthesis of benzimidazoles ( 8 ) in 53–94%, from another inexpensive, readily available, recyclable and magnetic separable, CuFe 2 O 4 nanocatalyst . The reactants were taken in toluene treated with catalyst at 110°C for 24 h and finally underwent oxidation by O 2 .…”

“…The reactants were stirred at 80°C in acetonitrile for 5-10 min giving 85-96% yield [21]. The reaction was invariably clean as the catalyst was magnetically separable on the completion of the reaction by an external magnet and capable to be reused for at least 12 times with a little loss in efficiency (Scheme 2, Table 1 [22]. The reactants were taken in toluene treated with catalyst at 110°C for 24 h and finally underwent oxidation by O 2 .…”