Pyridazine, also known as o-diazobenzene, is a six-membered heterocyclic compound containing two nitrogen heteroatoms in the 1 and 2 positions with a special structure and a wide biological activity. Pyridazine is more and more popular in drug development, and a variety of pyridazine drugs have been developed and marketed. From the perspective of the therapeutic field, pyridazine drug molecules are mainly used for tumor treatment, but also involve in many therapeutic fields such as inflammation, hypertension and cardiovascular disease. With the increase and in-depth of research, pyridazine drugs will play more roles in the treatment of diseases.
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.