Syntheses of Vitamin B₁ and its Related Compounds. VII

γ-Aceto-γ-chloropropyl acetate and CS2 were applied, under the presence of NH3, to 2-ethyl-4-amino-5-aminomethylpyrimidine, 2-benzyl-4-amino-5-aminomethylpyrimidine and 2-methyl-4-hydroxy-5-aminomethylpyrimidine, and subequent hydrolyses gave 3-(2′-ethyl-4′-aminopyrimidyl-5′)-methyl-4-methyl-5-β-hydroxyethyl-thiothiazolone (2), decompn. 225°; 3-(2′-benzyl-4′-aminopyrimidyl-5′)-methyl-4-methyl-5-β-hydroxyethyl-thiothiazolone (2), decompn. 224°; and 3-(2′-methyl-4′-hydroxypyrimidyl-5′)-methyl-4-methyl-5-β-hydroxyethyl-thiothiazolone (2), m.p. 206-208°, respectively. Desulfurization of the first two compounds gives respective thiochromine compounds. 2′-Ethyl compound possesses far stronger vitamin B1 action than vitamin B1.