18481-23-7 Bisbutitiamine Bisbutitiamine [JAN] Dithiobis(3-(1-(((4-amino-2-methylpyrimidin-5-yl)methyl)formylamino)ethylidene)propane-3,1-diyl) dibutyrate EINECS 242-370-8 O-Butyrylthiamine disulfide