A series of 4H, 8H-1,2,4-triazino[3,4-b]- 1,3,4-thiadiazin-4-ones 3a-i have
been synthesized by the reaction of 4-amino-6-substituted-3-mercapto-1,2,4
-triazin-5(4H)-ones 1 with substituted phenacyl bromides 2. These newly syn
thesized compounds have been tested for antimicrobial activities.