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92. Ring Closure Reactions of 3-Arylhydrazonoalkyl-quinolin-2-ones to 1 Aryl-pyrazolo[4,3-c]quinolin-2-ones
Stadlbauer W., Hojas G., J. Heterocyclic Chem., 41, 681-690 (2004)

4-Hydroxy-3-arylhydrazonoalkyl-2-quinolones 6 or reactive derivatives such as 3-arylhydrazonoalkyl-4-tosyloxy-2-quinolones 7 or 4-chloro-3-arylhydrazonoalkyl-2-quinolones 14, which are obtained via 3-acyl-4-hydroxyquinolones 4, 10 or 3-phenylaminomethylene-quinoline-2,4-diones 12, cyclize in excellent yields to 1-aryl-pyrazolo[4,3-c]quinolin-4-ones (11). The cyclization conditions were investigated by differential scanning calorimetry (DSC).

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