Structure-activity relationships of some 4-quinazolylthiosemicarbazides and their triazolo derivatives.

Eight 4-quinazolylthiosemicarbazides and nine of their structural analogues have been tested for antibacterial effects and for structure activity relationships. 9-Chloro-5-morpholino-1,2,4-triazolo[4,3-c]quinazoline-3-thione has demonstrated the highest antibacterial effect (MIC of 1 mg/L for E. coli and P. mirabilis and < 1 mg/L for S. aureus and B. subtilis). The most effective derivatives have the carbon aromatic ring substituted with chlorine and the pyrimidine ring with morpholine or with secondary amine group.