One-pot synthesis of novel fused mesoionic compounds: 1-substituted-5-thioxo-5,6-dihydro-[1,2,4]triazolo[1,5-c]quinazolin-1-ium-2-thiolates

Novel 1-substituted-5-thioxo-5,6-dihydro-[1,2,4]triazolo[1,5-c]quinazolin-1-ium-2-thiolates have been obtained by base catalyzed condensation of methyl 2-isothiocyanatobenzoate with thiosemicarbazides. The reaction occurs via intermediate N-(4-oxo-2-thioxo-1,4-dihydroquinazolin-3(2H)-yl)thioureas followed by cyclization with elimination of the oxygen atom as water and the angular product formation. All new synthesized compounds were fully characterized with elemental and spectroscopic analysis.