MANUFACTURE OF BENZIMIDAZOLONE %2<

摘要

o-Phenylenediamine is reacted with urea in water at elevated temp. (pref. 100-160 degrees C) to give benzimidiazol-2-one (useful as an intermediate for antimalarials and dyes) in good yield and in a purity such that reprecipitation or recrystallization is not required. Side-reactions are fewer than when o-phenylene diamine is reacted with urea in the melt, and a large excess of urea is not required.