The 1 : 1 salt of diamine and tartaric acid was formed by adding hot aqueous tartaric acid solution (1 equiv) to a hot ethanolic solution of the diamine, allowing the resulting mixture to cool slowly to room temperature, and collecting the crystalline solid by filtration. Recrystallization was carried out by suspending the salt in boiling water and adding just the right amount of boiling ethanol to effect solution. Two or in some cases three recrystallizations afforded fully resolved ...