Applications
o-phenylenediamine is used to prepare tiabendazole, pyrazinamide, morinamide, clemizole and chlormidazole. It is involved in the synthesis of benzimidazole by reacting with carboxylic acids and their derivatives. It is also used to prepare quinoxalinedione and mercaptoimidazoles by condensation with dimethyl oxalate and xanthate esters respectively. It reacts with nitrous acid to get benzotriazole, which finds application as a corrosion inhibitor. It is actively involved in the preparation of pharmaceuticals by reacting substituted o-phenylenediamine with various diketones.

Solubility
Soluble in alcohol, chloroform, ether, slightly soluble in water. Soluble in hot water.

Notes
Moisture and air sensitive. Keep the container tightly closed in a dry and well-ventilated place. Incompatible with strong oxidizing agents.