Thiazoline
title: "Thiazoline" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["thiazolines"] topic_path: "general/thiazolines" source: "https://en.wikipedia.org/wiki/Thiazoline" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
| Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 448615665 | ImageFile1 = 2,3-Dihydrothiazole.svg | ImageSize1 = 100px | ImageFile2 = 3-Thiazoline.svg | ImageSize2 = 100px | ImageFile3 = 4,5-Dihydrothiazole.svg | ImageSize3 = 100px | IUPACName = 2,3-Dihydrothiazole 2,5-Dihydrothiazole 4,5-Dihydrothiazole | OtherNames = 2,3-Dihydro-1,3-thiazole or 4-thiazoline 2,5-Dihydro-1,3-thiazole or 3-thiazoline 4,5-Dihydro-1,3-thiazole or 2-thiazoline |Section1={{Chembox Identifiers | index_label = (2,3) | index1_label = (2,5) | index2_label = (4,5) | CASNo = 504-79-0 | CASNo_Ref = | CASNo1 = 24576-55-4 | CASNo1_Ref = | CASNo2 = 504-79-0 | CASNo2_Ref = | PubChem = 151424 | PubChem1 = 15194654 | PubChem2 = 120269 | SMILES = C1=CSCN1 | SMILES1 = C1=NCSC1 | SMILES2 = C1CSC=N1 | InChI=1S/C3H5NS/c1-2-5-3-4-1/h1-2,4H,3H2 | InChIKey = OYJGEOAXBALSMM-UHFFFAOYSA-N | InChI1=1S/C3H5NS/c1-2-5-3-4-1/h1H,2-3H2 | InChIKey1 = JLPUISACQXFVRC-UHFFFAOYSA-N | InChI2=1S/C3H5NS/c1-2-5-3-4-1/h3H,1-2H2 | InChIKey2 = CBDKQYKMCICBOF-UHFFFAOYSA-N | ChemSpiderID = 133456 | ChemSpiderID1 = 10541467 | ChemSpiderID2 = 107368 |Section2={{Chembox Properties | C=3 | H=5 | N=1 | S=1 | Appearance = Colorless liquids | Density = | MeltingPt = | BoilingPtC = | BoilingPt_notes = | Solubility = |Section3={{Chembox Hazards | MainHazards = | FlashPt = | NFPA-H = | NFPA-F = | NFPA-R = | AutoignitionPt =
Thiazolines (; or dihydrothiazoles) are a group of isomeric 5-membered heterocyclic compounds containing both sulfur and nitrogen in the ring. Although unsubstituted thiazolines are rarely encountered themselves, their derivatives are more common and some are bioactive. For example, in a common post-translational modification, cysteine residues are converted into thiazolines.
The name thiazoline originates from the Hantzsch–Widman nomenclature.
Isomers
::figure[src="https://upload.wikimedia.org/wikipedia/commons/4/47/2-Thiazoline,_3-Thiazoline_und_4-Thiazoline.png" caption="2-Thiazoline, 3-Thiazoline and 4-Thiazoline (from left to right)"] ::
Three structural isomers of thiazoline exist depending on the position of the double bond. These forms do not readily interconvert and hence are not tautomers. Of these 2-thiazoline is the most common.
A fourth structure exists in which the N and S atoms are adjacent; this known as isothiazoline.
Synthesis
Thiazolines were first prepared by dialkylation of thioamides by Richard Willstatter in 1909. 2-Thiazolines are commonly prepared from 2-aminoethanethiols (e.g. cysteamine). They may also be synthesized via the Asinger reaction.
Applications
Many molecules contain thiazoline rings, one example being Firefly luciferin, the light-emitting molecule in fireflies. The amino acid cysteine is produced industrially from substituted thiazole.
References
References
- (2008). "Morphing peptide backbones into heterocycles". Proceedings of the National Academy of Sciences USA.
- (1909). "Über Thioformamid". Chem. Ber..
- (11 March 2009). "Overview of the Chemistry of 2-Thiazolines". Chemical Reviews.
- [[2-Aminothiazoline-4-carboxylic acid]] is an intermediate in the industrial synthesis of L-[[cysteine]].{{Ullmann. Karlheinz Drauz, Ian Grayson, Axel Kleemann, Hans-Peter Krimmer, Wolfgang Leuchtenberger, Christoph Weckbecker. (2006)
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