Molybdate sulfuric acid (MSA) has been demonstrated to be an efficient and reusable catalyst for the synthesis of quinoxaline and phenazine derivatives based on the condensation of 1,2-diketones and o-pheneylenediamines in ethanol as solvent at room temperature. Also, some novel polycyclic phenazines and quinoxalines are reported. The practical and simple method adopted in the present study led to very high yields of the products under mild conditions within short time intervals.

A new series of triheterocyclic compounds containing pyrazole, pyran, and pyrimidinone rings was synthesized via a one-pot condensation of ethylacetoacetate, hydrazine hydrate, barbituric acid, and aromatic aldehydes in the presence of catalytic amounts of titanium dioxide nanowires. Various functional groups were well tolerated under the optimized reaction conditions.