Formamide, N-​[(4-​amino-​2-​methyl-​5-​pyrimidinyl)​methyl]​-​N-​[4-​hydroxy-​1-​methyl-​2-​[[(tetrahydro-​2-​furanyl)​methyl]​dithio]​-​1-​buten-​1-​yl]​-​, hydrochloride (1:1)