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58. Reactions of 3-acyl-4-hydroxy-2(1H)-quinolones with nitrogen bases
Kappe Th., Aigner R., Jöbstl M., Hohengassner P., Stadlbauer W., Heterocycl. Commun., 1(5-6) (1995), 341-352.

Abstract: 3-Acyl-4-hydroxy-2-quinolones react with amines to yield 3-aminomethylene quinolinediones. With hydroxylamine the corresponding oximes are obtained, which cyclize on heating via a thermal Beckmann rearrangement to oxazolo[5,4-c]quinolones. The oxazoles can be ringopened in the presence of acids to give 3-acylamino-4-hydroxyquinolones. The hydrazones, obtained from 3-acyl-4-hydroxy-2-quinolones and hydrazines, cyclize either to pyrazolo[4,3-c]quinolones or give mixtures of pyrazoles and the dimeric azino-diethylidenequinolones.

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