Reactions of hydrazonoyl halides 6 with either 3-amino-2,3-dihydro-6-substi
tuted-3-thioxo-[1,2,4]-triazin-5(4H)ones 1(2) or 4-amino-3-methylthio-6-sub
stituted-[1,2,4]-triazin-5(4H)ones 3(4) gave [1,2,4]-triazino- [4,3-b][1,2,
4, 5]tetrazine derivatives 9(10), respectively. The mechanism of the reacti
ons studied is discussed.