Phillips‐Ladenburg Benzimidazole Synthesis

The preparation of benzimidazole by the condensation between ortho ‐amino aniline and acetic acid to produce different kinds of carboxylic acids in presence of dilute mineral acid is referred to as the Phillips–Ladenburg reaction. The study finds that condensation generally works for aliphatic acids and is feasible for aromatic acids if the condensations are carried out above 180°C in sealed reaction vessels. This reaction has been widely used in the preparation of benzimidazole derivatives.