2215-43-2Relevant articles and documents
Gold catalysis opens up a new route for the synthesis of benzimidazoylquinoxaline derivatives from biomass-derived products (glycerol)
Climent, Maria J.,Corma, Avelino,Iborra, Sara,Martinez-Silvestre, Sergio
, p. 3866 - 3874 (2013)
Process intensification by using well-defined solid catalysts able to perform one-pot multistep reactions is one of the open fronts in heterogeneous catalysis. This is even more relevant if new, more efficient synthesis routes are open. Herein, a gold catalyst was used to synthesize benzimidazoylquinoxalines compounds by two efficient and selective novel methods in a multistep one-pot methodology. The first method involved the synthesis of benzimidazoylquinoxaline compounds with the same substituents in both heterocycles through oxidation-cyclization of glycerol with o-phenylenediamine derivatives, whereas the second one allowed the synthesis of benzimidazoylquinoxalines compounds with different substituents in each aromatic ring through coupling of o-phenylenediamine derivatives with glyceraldehyde in a first stage to produce the benzimidazol compound as an intermediate, followed by an oxidation-cyclization with another o-phenylenediamine compound in a second stage. Both stages were performed by using gold nanoparticles supported on nanoparticulated ceria (Au/CeO2) as the catalyst and air as the oxidant, in absence of any homogeneous reagent. A reaction mechanism has been proposed. A smooth route: Benzimidazoylquinoxaline derivatives can be obtained in good yields through one-pot oxidative coupling of glycerol or glyceraldehydes with 1,2-phenylenediamines in a two-step reaction, using Au/CeO2 as the catalyst, base-free conditions, mild temperature, and air as the oxidant. Copyright
