View source for Chemistry:Asinger reaction

{{Reactionbox
|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-[[Chemistry:Thiazoline|thiazoline]]s and other related heterocycles.<ref>{{cite journal |last1=Asinger |first1=F. |last2=Offermanns |first2=H. |title=Syntheses with ketones, sulfur, and ammonia or amines at room temperature |journal=Angewandte Chemie International Edition in English |date=November 1967 |volume=6 |issue=11 |pages=907–919 |doi=10.1002/anie.196709071}}</ref> It is named after Friedrich Asinger who first reported it in 1956.<ref name="Asinger">{{cite journal |last1=Asinger |first1=F. |title=Über die gemeinsame Einwirkung von Schwefel und Ammoniak auf Ketone |journal=Angewandte Chemie |date=21 June 1956 |volume=68 |issue=12 |pages=413 |doi=10.1002/ange.19560681209|bibcode=1956AngCh..68..413A}}</ref>

[[File:Asinger Reaction 1.svg|thumb|400px|center|Asinger-reaction using ketones]]
[[File:Asinger Reaction 2.svg|thumb|400px|center|Asinger-reaction using [[Chemistry:Aldehyde|aldehyde]]s]]

==Process==
An α-halogenated carbonyl-component reacts with sodium hydrosulfide (NaSH) and forms a [[Chemistry:Thiol|Thiol]] ''in situ''. The thiol reacts directly with another carbonyl component and [[Chemistry:Ammonia|ammonia]] to form a thiazoline. The reaction works also by using elemental sulphur, an α–substituted [[Chemistry:Ketone|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-[[Chemistry:Thioketone|thioketone]] and ammonia.<ref name="Ariëns">{{cite journal |last1=Asinger |first1=F. |last2=Thiel |first2=M. |title=Einfache Synthesen und chemisches Verhalten neuer heterocyclischer Ringsysteme |journal=Angewandte Chemie |date=26 November 1958 |volume=70 |issue=22–23 |pages=667–683 |doi=10.1002/ange.19580702202|bibcode=1958AngCh..70..667A}}</ref>

A simplified route of the Asinger-reaction was developed at Degussa. An α-halogenated carbonyl compound reacts with sodium hydrosulfide (NaSH) and forms a [[Chemistry:Thiol|thiol]] ''in situ'' which reacts directly with aldehydes or ketones and ammonia to 3-thiazolines.<ref>{{cite journal |last1=Drauz |first1=Karlheinz |last2=Koban |first2=Hans Günter |last3=Martens |first3=Jürgen |last4=Schwarze |first4=Wolfgang |title=Phosphonic and Phosphinic Acid Analogs of Penicillamine |journal=Liebigs Annalen der Chemie |date=12 March 1985 |volume=1985 |issue=3 |pages=448–452 |doi=10.1002/jlac.198519850303}}</ref> The chemical industry developed based on the Asinger-reaction multi stage processes for the production of pharmaceuticals like D-penicillamine<ref>{{cite journal |last1=Weigert |first1=Wolfgang M. |last2=Offermanns |first2=Heribert |last3=Scherberich |first3=Paul |title=D-Penicillamin - Herstellung und Eigenschaften |journal=Angewandte Chemie |date=May 1975 |volume=87 |issue=10 |pages=372–378 |doi=10.1002/ange.19750871003|bibcode=1975AngCh..87..372W}}</ref> and the aminoacid <small>DL</small>-[[Chemistry:Cysteine|cysteine]].<ref>{{cite journal |last1=Martens |first1=Jürgen |last2=Offermanns |first2=Heribert |last3=Scherberich |first3=Paul |title=Einfache Synthese von racemischem Cystein |journal=Angewandte Chemie |date=August 1981 |volume=93 |issue=8 |pages=680–683 |doi=10.1002/ange.19810930808|bibcode=1981AngCh..93..680M}}</ref>

[[File:Asinger Reaction Penicilliamin.svg|thumb|600px|center|Synthesis of [[Chemistry:Penicillamine|penicillamine]] by the Asinger reaction]]

==References==
{{Reflist}}

==Literature==
*{{cite journal | journal = Angewandte Chemie | volume = 68 | issue = 11 | year = 1956| pages = 377| doi = 10.1002/ange.19560681109| title = Chemiker-Treffen Salzburg: Über die einfache und ergiebige Synthese von Thiazolonen | author = Friedrich Asinger}}
*{{cite journal | journal = Angewandte Chemie | volume = 68 | issue = 12 | year = 1956 | pages = 413 | doi = 10.1002/ange.19560681209 | title = Über die gemeinsame Einwirkung von Schwefel und Ammoniak auf Ketone | author = Friedrich Asinger| bibcode = 1956AngCh..68..413A}}
*{{cite journal | journal = Tetrahedron Letters | volume = 41 | issue = 38 | year = 2000 | pages = 7289&ndash;7292 | doi = 10.1016/S0040-4039(00)01266-1 | title = Synthesis of the first enantiomerically pure 3-thiazolines via Asinger reaction |author1=Imre Schlemminger |author2=Hans-Hermann Janknecht |author3=Wolfgang Maison |author4=Wolfgang Saak |author5=Jürgen Martens}}

[[Category:Multiple component reactions]]
[[Category:Name reactions]]
[[Category:Nitrogen heterocycle forming reactions]]

{{Sourceattribution|Asinger reaction}}