عنوان مقاله [English]
Among the various classes of nitrogen-containing heterocyclic compounds, quinoxalines play an important role as a basic skeleton for the design of a number of antibiotics. In addition, quinoxaline ring is a part of several pharmacological active substances of natural or synthetic origin. In this study, an ecofriendly method for the synthesis of cyclobutaquinoxaline-1,2-diol derivatives through cycloaddition reaction of O-phenylenediamine derivatives and squaric acid in EtOH as a green solvent in the presence of a catalytic amount of acetic acid under reflux condition is reported. Different diamine compounds such as 4-methylbenzene-1,2-diamine, 4-chlorobenzene-1,2-diamine, 4-nitrobenzene-1,2-diamine and pyridine-2,3-diamine were used. The structures of products were confirmed by FT-IR, 1H-NMR, 13C-NMR, and elemental analysis.the reaction of 2,3-diaminopyridine with squaric acid give the corresponding cyclobuta[e]pyrido[3,2-b]pyrazine-6,7-diol. According to the spectroscopic data (FT-IR and H-NMR data) in this reaction there might be three isomers in the cyclobuta[e]pyrido[3,2-b]pyrazine-6,7-diol. These isomers are tautomers. In summary, we have developed a new facile and ecofriendly protocol for the synthesis cyclobutaquinoxaline-1,2-diol derivatives from reaction of O-phenylenediamine derivatives and squaric acid.