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.
Benzodioxanes are a class of isomeric compounds with the molecular formula C8H8O2. The three isomers of benzodioxane are 1,2-benzodioxane, 1,3-benzodioxane and 1,4-benzodioxane. 1,4-Benzodioxane has long been a versatile template widely used to design molecules with diverse biological activities. Its use spans past decades in medicinal chemistry to today, involving many drug discovery strategies, not excluding the most advanced ones. 1,4-Benzodioxane derivatives have been described as agonists and antagonists of nicotinic, alpha-adrenergic and 5-HT receptor subtypes. 1,4-Benzodioxane derivatives have been also reported as antitumor and antibacterial agents.