Synthesis of some new biologically active thiadiazolotriazinones.

4-Amino-6-arylmethyl-3-mercapto-1,2,4-triazin-5(4H)-ones 1 are condensed with aromatic carboxylic acids, aryloxyacetic acids and anilinoacetic acids 2 to yield 7-substituted-3-arylmethyl-4H-1,3,4-thiadiazolo[2,3-c]-1,2,4-tr iazin-4-ones 3. Phosphorus oxychloride is used as cyclizing agent. Some of the newly synthesized compounds are screened for their antibacterial activities.