Synthesis of Structurally Diverse and Biologically Promising Polyheterocycles Involving Benzo[a]phenazin-5-ols

Nowadays, polyheterocyclic moieties are playing an important role in drug discovery. Many natural products contain a wide variety of polyheterocycles. Very recently among many other polyheterocycles, benzo[a]phenazine skeleton has gained huge attention due to their broad range of pharmacological efficacies which include anti-plasmodial, antitumor, antimalarial, anticancer, etc. activities. Interestingly, benzo[a]phenazin-5-ol derivatives have been used further as a template for the synthesis of structurally diverse biologically promising polyheterocycles under various reaction conditions. In this review, we have summarized all the recent developments related to the synthesis of structurally diverse biologically promising polyheterocycles involving benzo[a]phenazin-5-ol as a starting reagent or as an intermediate.