Piperazine is an organic compound consisting of a six-membered ring containing two nitrogen atoms in opposite positions in the ring. The chemical formula of piperazine is C4H10N2, and it is an important pharmaceutical intermediate. Pyrimidines and piperazines are known to be the backbone of many bulk compounds and important core structures for approved drugs; studies have shown that combining a pyridine ring with a piperazine moiety within a single structural framework enhances biological activity.
Cinnoline is a heterocyclic binuclear base containing two vicinal nitrogen atoms. Over the past two centuries, fused N-heterocyclic compounds have been widely used as valuable entities for expanding pharmacologically important reagents and have been recognized as an advantageous scaffold. Among the numerous fused N-heterocyclic compounds, cinnoline, quinoxaline, and quinazoline are important pharmacological agents, and a great deal of research has been done on this class of compounds. In medicinal chemistry, these N-heterocyclic compounds have a wide range of biological properties and can be used as synthetic intermediates, potential drug candidates and chemical probes.