3-Acyl-4-hydroxy-2-quinolones 1 react with amines to yield 3-aminomethylene quinolinediones 2. With hydroxylamine the corresponding oximes 3 are obtained, which cyclize on heating via a thermal Beckmann rearrangement to oxazolo[5,4-c]quinolones 4. The oxazoles can be ringopened in the presence of acids to give 3-acylamino-4-hydroxyquinolones 5. The hydrazones 6, obtained from 3-acyl-4-hydroxy-2-quinolones 1 and hydrazines, cyclize either to pyrazolo[4,3-c]quinolones 7 or give mixtures of 7 and the dimeric azino-diethylidenequinolones 8.
The reaction of camphoraniles 3a,b with "magic malonates" (bis-2,4,6-trichlorophenylmalonates) 4a,b leads to 4-hydroxy-2(1H)-pyridones attached to bornane ring system 6a-c in good yields. Less satisfactory yields were obtained with the diethyl malonate 5b. The reaction of an excess of diethyl malonate 5 itself with 3b yields the pyrono derivative 7, which can readily be degraded via the acetyl derivative 8 to the basic structure 9.
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