CHEMISTRY OF QUINOLINE-5,8-DIONES

Room-temperature acid-catalyzed methanolysis of 7-formamido-, 7-acetam ido-, or 7-isobutyramido-2-methylquinoline-5,8-diones (3, 4, 5) gives go od to excellent yields of 7-amino-2-methylquinoline-5,8-dione(6). S imple methods for the synthesis of novel 7-amino-6-chloro-2-methylquin oline-5,8-dione (7), 7-alkoxy-2-methylquinoline-5,8-diones (9-11), and quinoline quinols (12, 13) are described, and the corresponding mecha nisms are discussed. The replacement of an amino group on a quinone ri ng by alkoxy groups to produce 9-11 is reported for the first time and offers easy routes for the syntheses of these alkoxy derivatives. Als o, the 1,2-addition of an ethyl group (rather than the expected 1,4-ad dition of a cyano group) of the reagent diethylaluminum cyanide to a q uinolinedione is another novel reaction for the efficient preparation of quinoline quinols 12 and 13. An easy transformation of amino compou nd 6 to its acetamido derivative 4 is also described.