Danel Andrzej, Porębska Elżbieta, Markiel Kacper, Havrysh Oleksii, Kucharek Mateusz, Gut Arkadiusz, Uchacz Tomasz
The Faculty of Materials Engineering and Physics, Krakow University of Technology, Podchorążych Street 1, 30-084 Krakow, Poland.
The Faculty of Food Technology, Agricultural University, Balicka Street 122, 30-149 Krakow, Poland.
Molecules. 2023 Nov 15;28(22):7612. doi: 10.3390/molecules28227612.
Looking for effective synthetic methods for 1-pyrazolo[3,4-]quinolines preparation, we came across a procedure where, in a three-component reaction catalysed by L-proline, 4-aryl-4,9-dihydro-1-pyrazolo[3,4-]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-pyrazolo[3,4-]quinolines were prepared by another method and used as standards to compare the products formed in the original procedure.
在寻找制备1-吡唑并[3,4 -]喹啉的有效合成方法时，我们遇到了一种方法，即在L-脯氨酸催化的三组分反应中形成4-芳基-4,9-二氢-1-吡唑并[3,4 -]喹啉。这些化合物可以很容易地氧化成完全芳香体系，这为一种合成方法带来了希望，该方法可以替代例如常用于此目的的Friedländer缩合反应，尽管该反应受到合适底物可用性的严重限制。然而，在仔细重复该出版物中描述的步骤后，结果发现其中所述的化合物根本不形成。实际的化合物原来是4,4-(苯基-亚甲基)-双-(3-甲基-1-苯基吡唑-5-醇)。因此，通过另一种方法制备了4-芳基-4,9-二氢-1-吡唑并[3,4 -]喹啉，并用作标准品来比较原始步骤中形成的产物。
