A facile and efficient method for hydroxylation of azabenzanthrone compounds

A novel and facile method of introducing 4-hydroxyl group into the aromatic ring of azabenzanthrone compounds was carried out by reacting azabenzanthrone compounds with hydrazine hydrate or hydroxylamine hydrochloride and sodium hydroxide in diethylene glycol (DEG) solvent. The mechanism of reaction may involve an amino intermediate and follow a hydroxyl substitution process.