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.
Pyrazoline is a heterocyclic chemical compound with the molecular formula C3H6N2. Pyrazolines are well-known and important nitrogen-containing five-membered ring heterocyclic compounds. Pyrazoline derivatives have numerous prominent pharmacological effects, such as antimicrobial, anti-inflammatory, analgesic, antidepressant and anticancer.