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.
Pyrrolidine, also known as tetrahydropyrrole, is a saturated five-membered heterocyclic ring, which is miscible with water. Pyrrolidine exists in many alkaloids and drug molecules, such as kappa opioids, antagonists of dopamine D4 receptors, and HIV reverse transcriptase inhibitors.
The molecular structure of cyclobutane has four carbon atoms, and its four carbon atoms are not in the same plane, which is the folded conformation of cyclobutane. Cyclobutane itself is not of commercial or biological interest, but more complex derivatives are important in biology and biotechnology. Currently, nine FDA-approved drugs contain the cyclobutane structure. From the perspective of therapeutic areas, cyclobutyl drugs are mainly distributed in popular areas such as tumors, neurological diseases, infectious diseases, endocrine and metabolic diseases.