Asinger reaction

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title: "Asinger reaction" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["multiple-component-reactions", "name-reactions", "sulfur-heterocycle-forming-reactions", "nitrogen-heterocycle-forming-reactions"] description: "Chemical reaction" topic_path: "general/multiple-component-reactions" source: "https://en.wikipedia.org/wiki/Asinger_reaction" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Chemical reaction ::

|Name = Asinger reaction |Type = Ring forming reaction |NamedAfter = Friedrich Asinger |Section3 = {{Reactionbox Identifiers |RSC_ontology_id = 0000688 The Asinger reaction (sometimes referred to as the Asinger-4 component reaction or A-4CR for short) is a multicomponent reaction for the synthesis of 3-thiazolines and other related heterocycles. It is named after Friedrich Asinger who first reported it in 1956.

::figure[src="https://upload.wikimedia.org/wikipedia/commons/0/04/Asinger_Reaction_1.svg" caption="Asinger-reaction using [[ketone]]s"] ::

::figure[src="https://upload.wikimedia.org/wikipedia/commons/9/94/Asinger_Reaction_2.svg" caption="Asinger-reaction using [[aldehyde]]s"] ::

Process

An α-halogenated carbonyl-component reacts with sodium hydrosulfide (NaSH) and forms a thiol in situ. The thiol reacts directly with another carbonyl component and ammonia to form a thiazoline. The reaction works also by using elemental sulphur, an α–substituted ketone, another carbonyl component and ammonia; in this case, a mixture of products is formed.

The formation of 3-thiazolines also occurs by using α-thioaldehyde or α-thioketone and ammonia.

A simplified route of the Asinger-reaction was developed at Degussa. An α-halogenated carbonyl compound reacts with sodium hydrosulfide (NaSH) and forms a thiol in situ which reacts directly with aldehydes or ketones and ammonia to 3-thiazolines. The chemical industry developed based on the Asinger-reaction multi stage processes for the production of pharmaceuticals like D-penicillamine and the aminoacid DL-cysteine.

::figure[src="https://upload.wikimedia.org/wikipedia/commons/c/c6/Asinger_Reaction_Penicilliamin.svg" caption="Synthesis of [[penicillamine]] by the Asinger reaction"] ::

References

Literature

References

1. (November 1967). "Syntheses with ketones, sulfur, and ammonia or amines at room temperature". Angewandte Chemie International Edition in English.
2. (21 June 1956). "Über die gemeinsame Einwirkung von Schwefel und Ammoniak auf Ketone". Angewandte Chemie.
3. (26 November 1958). "Einfache Synthesen und chemisches Verhalten neuer heterocyclischer Ringsysteme". Angewandte Chemie.
4. (12 March 1985). "Phosphonic and Phosphinic Acid Analogs of Penicillamine". Liebigs Annalen der Chemie.
5. (May 1975). "D-Penicillamin - Herstellung und Eigenschaften". Angewandte Chemie.
6. (August 1981). "Einfache Synthese von racemischem Cystein". Angewandte Chemie.

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