Oxythiamine hexafluorophosphate monohydrate,a thiamine antagonist with the same conformation as ­thiamine

In the title compound, 3‐(3,4‐di­hydro‐2‐methyl‐4‐oxopyrimidin‐5‐yl)­methyl]‐5‐(2‐hydroxy­ethyl)‐4‐methyl­thia­zolium hexa­fluoro­phosphate monohydrate, C₁₂H₁₆N₃O₂S⁺·PF₆^?·H₂O, oxy­thi­amine is a monovalent cation with a neutral oxo­pyrimidine ring. The mol­ecule assumes the F conformation, which is a common form for thi­amine but which is substantially different from the unusual V conformation found in the chloride and hydro­chloride salts of oxy­thi­amine. The anion‐bridging interaction, C—H?anion?pyrimidine, is emphasized as being important for stabilization of the F conformation.