Biomass into chemicals: One-pot two- and three-step synthesis of quinoxalines from biomass-derived glycols and 1,2-dinitrobenzene derivatives using supported gold nanoparticles as catalysts

Gold nanoparticles supported on nanoparticulated ceria (Au/CeO2) is an active, selective, and reusable catalyst to perform one-pot two- and three-step synthesis of quinoxalines. [Display omitted] ► Developed efficient and selective synthesis of quinoxalines from biomass diols. ► A reaction mechanism for quinoxaline derivative synthesis is proposed. ► Au/CeO2 and Au/HT produced 2-methylquinoxaline with selectivities higher than 87%. ► Eighty-three percentage yield of 2-methylquinoxaline from PG and 1,2-dinitrobenzene was achieved. ► Au/CeO2 can be easily recovered and reused with a small loss of activity. An efficient and selective one-pot two-step method, for the synthesis of quinoxalines by oxidative coupling of vicinal diols with 1,2-phenylenediamine derivatives, has been developed by using gold nanoparticles supported on nanoparticulated ceria (Au/CeO2) or hydrotalcite (Au/HT) as catalysts and air as oxidant, in the absence of any homogeneous base. Reaction kinetics shows that the reaction controlling step is the oxidation of the diol to α-hydroxycarbonyl compound. Furthermore, a one-pot three-step synthesis of 2-methylquinoxaline starting from 1,2-dinitrobenzene and 1,2-propanediol has been successfully carried out with 98% conversion and 83% global yield to the final product.