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.
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.
Thiazoles are very important functional groups in medicinal chemistry. They act as ligands on a variety of biological matrices. Thiazoles are used in a wide range of therapeutic applications, such as antibacterial, antiretroviral, antifungal, antiallergic, antihypertensive, pain treatment, and to control symptoms of schizophrenia.