The paper describes syntheses of 4,9-dihydro-3-methyl-4-oxo-1H(2H)-pyrazolo[3,4-b]quinoline (Ia), its 1-methyl derivative (Ib), 2-methyl derivative (IIa), 9-methyl derivative (Ic), 1,9-dimethyl derivative (Id) and 2,9-dimethyl derivative (IIb). Sodium salts of compounds Ia, Ib, Ic and IIa were methylated with methyl iodide in dimethylformamide at room temperature, compounds Id and IIb were demethylated with pyridine hydrochloride. The compounds prepared were tested for antiviral activity in vivo in mice against influenza virus A2-Hongkong and the Encephalomyocarditis virus.

Polymeric dihydroquinolines, which are commonly used as antioxidants for macromolecular systems, were prepared by acid-catalyzed condensation of acetone with aniline. The final products may differ in quality according to the purity of the starting materials and conditions of preparation. In the present work, three commercial antioxidants of the type of polymeric 2,2,4-trimethyl-l ,2-dihydroquinoline were mutually compared from the chemical point of view. Some of the components of the antioxidants were identified by mass spectrometry after prior separation using GPC and LLC-RP. ZUSAMMENFASSUNG:Polymere Dihydrochinoline, die man oft als Antioxydantien fur verschiedene makromolekulare Systeme einsetzt, wurden durch saurekatalysierte Kondensation aus Aceton mit Anilin hergestellt. In Abhiingigkeit vom Reinheitsgrad der Ausgangsstoffe und von den Reaktionsbedingungen k6nnen sich die Endprodukte qualitativ voneinander unterscheiden. In dieser Arbeit wurden die chemischen Eigenschaften von drei kommerziellen Antioxydantien, die aus polymerisiertem 2,2,4-Trimethyl-1,2-dihydrochinolin bestehen, verglichen. Einige durch Gel-und Umkehrphasenflussigkeitschromatographie abgetrennte Bestandteile der Antioxydantien wurden mit Hilfe der Massenspektroskopie identifiziert.

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