Alternative Synthesis of 2,4-Substituted-1,3-thiazines and 2,5-Substituted-thiazole Derivatives
Aneasy and convenient route for the synthesis of 2,4-substituted thiazine (3–6) and 2,5-substituted thiazole (16) derivatives from phenacetamidines and glycine methyl ester is reported. To the best of our knowledge, this is the first report in which phenacetamidines have been utilized as precursors for thiazine synthesis. The syntheses of novel cyclic fused 1,3-diazabutadienes 13 and 2-aza-1,3-butadiene 17, and iodocyclization of 17 leading to the formation of thiazole 16a are also reported. In this paper a total of twenty novel compounds are reported.
Keywords: Phenacetamidines, 1,3-thiazines, thiazoles, cyclizations