A synthesis of 4-quinolone-3-carboxylic acids via pyrolysis of N- aryldioxopyrrolines
A synthesis of 4-quinolone-3-carboxylic acids (8) was achieved by pyrolysis of 4,5-dimethoxycarbonyl-1-aryl-1H-pyrrole-2,3-diones (3) followed by selective demethoxycarbonylation of the resulting 2,3-dimethoxycarbonyl-4- quinolones (4) in excellent overall yields.