Synthesis, reactions and biological evaluation of some 1,2,4‐triazine derivatives

6‐Substituted benzyl‐4‐phenyl‐3‐thioxo‐2,3,4,5‐tetrahydro‐1,2,4‐triazin‐5‐ones 3a‐d were prepared and converted into their corresponding 3‐methylthio derivatives 4a‐d. Reaction of compounds 4a‐d with hydrazine hydrate gave the corresponding 4‐amino‐3‐anilino‐4,5‐dihydro‐1,2,4‐triazin‐5‐ones 5a‐d. 6‐Substituted benzyl‐4‐phenyl‐2,3,4,5‐tetrahydro‐1,2,4‐triazin‐3,5‐diones 9a‐c were synthesized and allowed to react with hydrazine hydrate to give the corresponding 6‐substituted benzyl‐4‐amino‐2,3,4,5‐tetrahydro‐1,2,4‐triazin‐3,5‐diones 10a‐c. The biological evaluation of some of these triazines is described. All compounds were screened for antiviral, antibacterial, antimycobacterial, antifungal and antiyeast activity. No important biological activity was found. Copyright © 1988 Journal of Heterocyclic Chemistry