Multicomponent Synthesis of 4-Aryl-4,9-dihydro-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolines Using L-Proline as a Catalyst—Does It Really Proceed?
Looking for effective synthetic methods for 1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolines preparation, we came across a procedure where, in a three-component reaction catalysed by L-proline, 4-aryl-4,9-dihydro-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolines ar...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-11-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/28/22/7612 |
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| author | Andrzej Danel Elżbieta Porębska Kacper Markiel Oleksii Havrysh Mateusz Kucharek Arkadiusz Gut Tomasz Uchacz |
| author_facet | Andrzej Danel Elżbieta Porębska Kacper Markiel Oleksii Havrysh Mateusz Kucharek Arkadiusz Gut Tomasz Uchacz |
| author_sort | Andrzej Danel |
| collection | DOAJ |
| description | Looking for effective synthetic methods for 1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolines preparation, we came across a procedure where, in a three-component reaction catalysed by L-proline, 4-aryl-4,9-dihydro-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolines are formed. These compounds can be easily oxidised to a fully aromatic system, which gives hope for a synthetic method that could replace, e.g., Friedländer condensation, often used for this purpose, even though severely limited by the availability of suitable substrates. However, after careful repetition of the procedures described in the publication, it turned out that the compounds described therein do not form at all. The actual compounds turned out to be 4,4-(phenyl-methylene)-bis-(3-methyl-1-phenylpyrazol-5-oles). Therefore, 4-Aryl-4,9-dihydro-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolines were prepared by another method and used as standards to compare the products formed in the original procedure. |
| first_indexed | 2024-03-09T16:34:43Z |
| format | Article |
| id | doaj.art-dcbb669ee40e44f9b62206a3f278a94b |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-09T16:34:43Z |
| publishDate | 2023-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-dcbb669ee40e44f9b62206a3f278a94b2023-11-24T14:58:25ZengMDPI AGMolecules1420-30492023-11-012822761210.3390/molecules28227612Multicomponent Synthesis of 4-Aryl-4,9-dihydro-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolines Using L-Proline as a Catalyst—Does It Really Proceed?Andrzej Danel0Elżbieta Porębska1Kacper Markiel2Oleksii Havrysh3Mateusz Kucharek4Arkadiusz Gut5Tomasz Uchacz6The Faculty of Materials Engineering and Physics, Krakow University of Technology, Podchorążych Street 1, 30-084 Krakow, PolandThe Faculty of Materials Engineering and Physics, Krakow University of Technology, Podchorążych Street 1, 30-084 Krakow, PolandThe Faculty of Materials Engineering and Physics, Krakow University of Technology, Podchorążych Street 1, 30-084 Krakow, PolandThe Faculty of Materials Engineering and Physics, Krakow University of Technology, Podchorążych Street 1, 30-084 Krakow, PolandThe Faculty of Food Technology, Agricultural University, Balicka Street 122, 30-149 Krakow, PolandThe Faculty of Chemistry, Jagiellonian University, Gronostajowa Street 2, 30-387 Krakow, PolandThe Faculty of Chemistry, Jagiellonian University, Gronostajowa Street 2, 30-387 Krakow, PolandLooking for effective synthetic methods for 1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolines preparation, we came across a procedure where, in a three-component reaction catalysed by L-proline, 4-aryl-4,9-dihydro-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolines are formed. These compounds can be easily oxidised to a fully aromatic system, which gives hope for a synthetic method that could replace, e.g., Friedländer condensation, often used for this purpose, even though severely limited by the availability of suitable substrates. However, after careful repetition of the procedures described in the publication, it turned out that the compounds described therein do not form at all. The actual compounds turned out to be 4,4-(phenyl-methylene)-bis-(3-methyl-1-phenylpyrazol-5-oles). Therefore, 4-Aryl-4,9-dihydro-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolines were prepared by another method and used as standards to compare the products formed in the original procedure.https://www.mdpi.com/1420-3049/28/22/76124-aryl-4,9<i>H</i>-3-methyl-1-phenyl-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolinemulti-component reactionsL-proline4,4-(phenyl-methylene)-bis-(3-methyl-1-phenylpyrazol-5-oles) |
| spellingShingle | Andrzej Danel Elżbieta Porębska Kacper Markiel Oleksii Havrysh Mateusz Kucharek Arkadiusz Gut Tomasz Uchacz Multicomponent Synthesis of 4-Aryl-4,9-dihydro-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolines Using L-Proline as a Catalyst—Does It Really Proceed? Molecules 4-aryl-4,9<i>H</i>-3-methyl-1-phenyl-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinoline multi-component reactions L-proline 4,4-(phenyl-methylene)-bis-(3-methyl-1-phenylpyrazol-5-oles) |
| title | Multicomponent Synthesis of 4-Aryl-4,9-dihydro-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolines Using L-Proline as a Catalyst—Does It Really Proceed? |
| title_full | Multicomponent Synthesis of 4-Aryl-4,9-dihydro-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolines Using L-Proline as a Catalyst—Does It Really Proceed? |
| title_fullStr | Multicomponent Synthesis of 4-Aryl-4,9-dihydro-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolines Using L-Proline as a Catalyst—Does It Really Proceed? |
| title_full_unstemmed | Multicomponent Synthesis of 4-Aryl-4,9-dihydro-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolines Using L-Proline as a Catalyst—Does It Really Proceed? |
| title_short | Multicomponent Synthesis of 4-Aryl-4,9-dihydro-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinolines Using L-Proline as a Catalyst—Does It Really Proceed? |
| title_sort | multicomponent synthesis of 4 aryl 4 9 dihydro 1 i h i pyrazolo 3 4 i b i quinolines using l proline as a catalyst does it really proceed |
| topic | 4-aryl-4,9<i>H</i>-3-methyl-1-phenyl-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinoline multi-component reactions L-proline 4,4-(phenyl-methylene)-bis-(3-methyl-1-phenylpyrazol-5-oles) |
| url | https://www.mdpi.com/1420-3049/28/22/7612 |
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