作者:Werner Fiala、Wolfgang Stadlbauer
DOI:10.1002/prac.19933350203
日期:——
Chlorination of 1-substituted 3-formyl-4-hydroxy-2-quinolones (1a, b) with phosphorylchloride leads to 4-chloro-3-dichloromethylquinolones (2), which can be hydrolyzed to 4-chloro-3-formylquinolones (4). From the anilinomethylene quinolinediones (3), at low temperatures the formylquinolones 4 can be obtained directly, whereas at high temperatures cleavage of the tautomeric azomethine moiety followed by subsequent ring closure to the naphthyridines (7) takes place. With 1-unsubstituted 3-formyl-4-hydroxy-2-quinolones (1d) either the 3-dichloromethylquinolone (2d) or the 2,4-dichloro-3-dichloromethylquinoline (10) is obtained depending on the reaction conditions. Similar results are obtained with the 1-unsubstituted anilinomethylene compounds (3). Attempts to obtain the 3-formyl-2,4-dichloroquinoline (11) were unsuccessful because in all experiments the 2-chloro-group was converted to an oxygen function.