[1,2,5]Thiadiazolo[3,4-b]pyrazine-5,6(4H,7H)-dione

Fused 1,2,5-chalcogenadiazoles are often used as biologically active compounds and organic optovoltaic materials. [1,2,5]Thiadiazolo[3,4-b]pyrazines are much less studied due to difficulties in their preparation. In this communication, [1,2,5]thiadiazolo[3,4-b]pyrazine-5,6(4H,7H)-dione, a key precursor for the synthesis of 5,6-dihalo-[1,2,5]thiadiazolo[3,4-b]pyrazines, was prepared via condensation of 1,2,5-thiadiazole-3,4-diamine with oxalic acid or oxalyl chloride. The structure of the newly synthesized compound was established by elemental analysis, high-resolution mass spectrometry, 1H and 13C NMR, IR spectroscopy, and mass spectrometry.