Tetraazapentalenes (R = CH3 and CH2=CHCH2) reacted with isocyanates to give new types of tetraazapentalenes, (2) and (3). The compounds, 2 and 3 were also obtained by the reaction of isocyanates with thiadiazolopyrimidines.
The synthesis of unsymmetrical tetraazapentalene derivatives was achieved by the reaction of thiadiazole derivatives (2) with various isothiocyanates. Compounds 2 were easily derived from symmetrical tetraazapentalene derivatives.