Studies on Pyrimidine Derivatives and Related Compounds. XLVI. The Reactions of Diethyl Acetylphosphonate with Thiamine : Takamizawa Reaction (5).

Abstract

3-(2-Hydroxy-and 2-acetoxy) ethyl-1, 4, 9-trimethyl-1, 6-dihydropyrimido [4', 5'-4, 5] pyrimido-[2, 3-c] [1, 4] thiazine (IIIb and IVb) were obtained by the reaction of thiamine (I) and diethyl acetylphosphonate (IIb). Alkaline hydrolysis of IIIb or IVb gave 2-methyl-4-(2-methyl-4-amino-5-pyrimidinyl)-methyl-5-methyl-6-(2-hydroxy) ethyl-2H-1, 4-thiazin-3 (4H)-one (Vb), which was decomposed to give VIIb by conc. HCl. The structures of IVb and VIIb were confirmed by the synthetic method.