Pyrimidine-fused Dinitrogenous Penta-heterocycles as a Privileged Scaffold for Anti-Cancer Drug Discovery

Pyrimidine-fused derivatives that are the inextricable part of DNA and RNA play a key role in the normal life cycle of cells. Pyrimidine-fused dinitrogenous penta-heterocycles, including pyrazolopyrimidines and imidazopyrimidines are a special class of pyrimidine-fused compounds contributing to an important portion in anti-cancer drug discovery, which has been discovered as the core structure for promising anti-cancer agents used in the clinic or clinical evaluations. Pyrimidinefused dinitrogenous penta-heterocycles have become one privileged scaffold for anti-cancer drug discovery. This review consists of the recent progress of pyrimidine-fused dinitrogenous pentaheterocycles as anti-cancer agents and their synthetic strategies. In addition, this review also summarizes some key structure-activity relationships (SARs) of pyrimidine-fused dinitrogenous pentaheterocycle derivatives as anti-cancer agents.