3-((4-amino-2-ethylpyrimidin-5-yl)methyl)-5-(2-hydroxyethyl)-4-methylthiazol-3-ium bromide hydrobromide Ethyl Thiamine Bromide Hydrobromide Thiamine nitrate EP Impurity F Thiamine Impurity F HBr Thiamine Impurity 6（Thiamine EP Impurity F） 3-((4-amino-2-ethylpyrimidin-5-yl)methyl)