Abstract The reaction of 4-hydroxy-2-quinolone (1) with malonyl chlorides 2 in the presence of N, N-dimethylaniline yields the linear pyrono-quinolones 4. These are thermically rearranged to angular derivatives 5, which can also be obtained by direct condensation of 1 with trichlorophenyl malonates 3. The reaction of 4-benzyloxy-2-quinolone with 2a gives the mesoionic 1, 3-oxazine derivative 8.
![4-hydroxy-3-phenyl-10H-pyrano[2,3-b]quinoline-2,5-dione结构式](https://image.chemsrc.com/caspic/229/62668-76-2.png)
![3-benzyl-4-hydroxy-10H-pyrano[2,3-b]quinoline-2,5-dione结构式](https://image.chemsrc.com/caspic/191/62668-77-3.png)
![4-hydroxy-3-phenyl-6H-pyrano[3,2-c]quinoline-2,5-dione结构式](https://image.chemsrc.com/caspic/153/62668-78-4.png)
