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.
Oxazoles are heterocyclic aromatic compounds containing one oxygen atom and one nitrogen atom, separated by a carbon atom. The presence of two heteroatoms (oxygen and nitrogen) provides possible interactions (hydrogen, hydrophobic, van der Waals or dipole bonds) with a wide range of receptors and enzymes. Oxazole rings are valuable heterocyclic scaffolds for the design of novel therapeutics with anticancer, antiviral, antibacterial, anti-inflammatory, neuroprotective, antidiabetic, and antidepressant properties due to their wide range of targets and biological activities.
Thiazolidine is a heterocyclic organic compound, which is a five-membered saturated ring with a thioether group and an amine group. It is the sulfur analog of oxazolidine. Thiazolidine derivatives have many uses and have a broad spectrum of biological activities. For example, the drug pioglitazone contains a thiazolidine ring. Thiazolidine has three isomers, 2-, 3-, and 4-. Derivatives with a 2-thiazoline ring are the most common.