University of Tehran Journal of Sciences, Islamic Republic of Iran 1016-1104 10 1 1999 03 01 SELECTIVE CYCLIZATION AND IS OMERIZATION OF 3-PROPARGYLTHIO- 1,2,4- BENZOTRIAZINE TO THIAZOLO [2,3-C] [1,2,4] BENZOTRIAZINE - 31347 EN Journal Article The method cited in the literature for synthesis of 1,2- dihydro 3- thioxo - 1,2,4- benzotriazine 1 was improved .1 was condensed with propargyl bromide to afford 3 - propargylthio – 1,2,4 -benzotriazine 5. Transformation of this compound to 9H-3- methylthiazolo [2,3-c] [1,2,4] benzotriazine ( 3, R = Me) was performed in the presence of Na O Me / MeOH . Orientation of this selective cyclization was ascertained by (N.O.E.) NMR experiment https://jsciences.ut.ac.ir/article_31347_fbdf42a1e05260c8a58057ed7e2eb77b.pdf