Hexafluoroisopropanol as solvent and promotor in the Paal-Knorr synthesis of N-substituted diaryl pyrroles

An additive-free synthesis of challenging N-substituted aryl pyrroles from the often poorly soluble corresponding 1,4-diketones by means of the Paal-Knorr pyrrole synthesis is reported, which makes use of the unique properties of 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) as a solvent and reaction pro...

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Bibliographic Details
Main Authors: Schirmacher, Robert H. E. (Author) , Rösch, Daniel (Author) , Thomas, Franziska (Author)
Format: Article (Journal)
Language:English
Published: 6 February 2021
In: Tetrahedron
Year: 2021, Volume: 83, Pages: 1-16
ISSN:1464-5416
DOI:10.1016/j.tet.2021.131985
Online Access:Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1016/j.tet.2021.131985
Verlag, lizenzpflichtig, Volltext: https://www.sciencedirect.com/science/article/pii/S0040402021000843
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Author Notes:Robert H.E. Schirmacher, Daniel Rösch, Franziska Thomas
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Summary:An additive-free synthesis of challenging N-substituted aryl pyrroles from the often poorly soluble corresponding 1,4-diketones by means of the Paal-Knorr pyrrole synthesis is reported, which makes use of the unique properties of 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) as a solvent and reaction promotor. Our procedure offers simple execution and purification as well as easy scale-up and can be applied in the Paal-Knorr synthesis of a large number of structurally diverse pyrroles including the synthetically challenging tetra- and penta-substituted pyrroles in moderate to excellent yields. HFIP can also be used as solvent in the Paal-Knorr synthesis of furans and thiophenes; however, the solvent effect is more pronounced in synthesis of pyrroles.
Item Description:Gesehen am 04.08.2021
Physical Description:Online Resource
ISSN:1464-5416
DOI:10.1016/j.tet.2021.131985