Study of the Products of Iodocyclization of 4-Allyl-5-phenyl-1,2,4-triazole-3-thione

The interaction of 4-allyl-5-phenyl-1,2,4-triazole-3-thione with iodine proceeds with the formation of a mixture of 6-iodomethyl-3-phenyl-5,6-dihydrothiazolo2,3-c]-1,2,4-triazole and 6-iodo-3-phenyl-6,7-dihydro-5H-1,2,4-triazolo3,4-b]-1,3-thiazine. The structures of the cyclization products obtained were established on the basis of the ¹H NMR spectra of their dehydroiodinated derivatives. 6-Methyl-3-phenylthiazolo2,3-c]-1,2,4-triazole, 3-phenyl-5H-1,2,4-triazolo3,4-b]-1,3-thiazine, and 3-phenyl-7H-1,2,4-triazolo3,4-b]-1,3-thiazine are formed on eliminating HI from the cyclization products.