Abstract
6-Benzyl-3-(arylmethylidenehydrazino)-
as-triazin-5(4
H)-ones
4
underwent regioselective cyclization upon treatment with either bromine in acetic acid containing sodium acetate or with ferric chloride in refluxing ethanol to give the respective
s-triazolo[4,3-
b]-
as-triazin-7(8
H)-ones
7
in overall good yields. The regioselectivity in the studied reactions was elucidated by comparison of
13C NMR spectra of
7
and their methyl derivatives with those of their regioisomers prepared by independent methods.
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