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.
Tetrahydrothiophene is a sulfur-containing saturated heterocyclic compound obtained by catalytic hydrogenation of thiophene. After thiophene is reduced to tetrahydrothiophene, it no longer has a conjugated system and aromaticity. Therefore, tetrahydrothiophene shows the properties of general thioethers. Easily oxidized to sulfoxides and sulfones. Tetrahydrothiophene can be used as a raw material for the production of pharmaceuticals, pesticides and photochemicals.