Deuterium Studies in the Cyclization and Isomerization of 3-Propargylmercapto-1,2,4-Triazines to Thiazolo[3,2-B]-[1,2,4] Triazines

Abstract

Transformation of 3-propargylmercapto-1,2,4-triazin-5(2H)-one (2; R=H or Me) to the corresponding 2-dihydro-3-methylenethiazolo[3,2-b][1,2,4]triazin-7-one (3; R=H or Me) is performed in a dilute solution of triethylamine in MeOH. Compound (3; R=Me) was isomerized to 3,6-dimethyl-thiazolo[3,2-b][1,2,4]-triazin-5-one (4; R=Me) in 5% aqueous sodium hydroxide. Treatment of (3; R=Me) with 5% sodium deuteroxide gave 6-methyl-3-monodeu-terated methyl-2-D-thiazolo[3,2-b][1,2,4]-triazin-7-one (5, R=Me).

Key Words:

• Deuterium studies
• cyclization
• Propargylmercapto-triazines
• Thiazolo-triazines