Thiophene is a five-membered heterocyclic compound containing a sulfur heteroatom with the molecular formula C4H4S. Thiophene is aromatic and is very similar to benzene; electrophilic substitution reaction is easier than benzene, and it is mainly substituted at the 2-position. Thiophene ring system has certain stability to oxidant.
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.
Pyrrole is a five membered heterocyclic compound with the molecular formula of C4H5N. Pyrrole has a ring composed of four carbon atoms and one nitrogen atom. Pyrrole is easy to polymerize in the air. Pyrrole is the parent compound of many important biological substances (such as bile pigment, porphyrin and chlorophyll). Pyrrole scaffolds are widely used in biological and pharmaceutical fields. Pyrrole is a special heterocyclic scaffold, which exists in many natural products, drug molecules and pesticides, and has shown its application in materials science.