Affiliation:
1. The Faculty of Materials Engineering and Physics, Krakow University of Technology, Podchorążych Street 1, 30-084 Krakow, Poland
2. The Faculty of Food Technology, Agricultural University, Balicka Street 122, 30-149 Krakow, Poland
3. The Faculty of Chemistry, Jagiellonian University, Gronostajowa Street 2, 30-387 Krakow, Poland
Abstract
Looking for effective synthetic methods for 1H-pyrazolo[3,4-b]quinolines preparation, we came across a procedure where, in a three-component reaction catalysed by L-proline, 4-aryl-4,9-dihydro-1H-pyrazolo[3,4-b]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-1H-pyrazolo[3,4-b]quinolines were prepared by another method and used as standards to compare the products formed in the original procedure.
Subject
Chemistry (miscellaneous),Analytical Chemistry,Organic Chemistry,Physical and Theoretical Chemistry,Molecular Medicine,Drug Discovery,Pharmaceutical Science