Ring transformation of 1,3,4-oxadiazole to s-triazole-fused heterocycles. New synthetic route for thiazolo[2,3-c]-s-triazole and 7H-s-triazolo[3,4-b][1,3,4]thiadiazine
Ring transformation of 1,3,4-oxadiazole to s-triazole-fused heterocycles. New synthetic route for thiazolo[2,3-c]-s-triazole and 7H-s-triazolo[3,4-b][1,3,4]thiadiazine
Cyclopentano[c]-s-triazoles were synthesized by intramolecular ringtransformation starting from y-keto-l,3,4-oxadiazoles 5 and 9. The required functionality for this intramolecular reaction was established by (i) the reaction of lithiated 2-methyl-l,3,4-oxadiazole 4 with the methyl enol ether of α-bromo ketones followed by hydrolysis; (ii) reductive amination of γ-ketones 5 and 9 to further reorganized