Accurate ab initio calculations at the B3LYP/6-311 G** level have been performed on anionic and neutral structures of 4,5-dihydro-5-oxo[1,2,4]triazolo[1,5-a]pyrimidine, 4,7-dihydro-7-oxo[1,2,4]triazolo[1,5-a]pyrimidine, and 4,5-dihydro-7-amino-5-oxo[1,2,4]triazolo[1,5-a]pyrimidine compounds. The quality of the theoretical results has been tested against the experimental X-ray structures for the...
