Syntheses of 3-aminoquinoline-2,4(1H,3H)-diones

Abstract

3-Chloro- and 3-bromoquinoline-2,4(1H,3H)-diones react with excess of primary alkyl or arylamines in dimethylformamide to the corresponding 3-alkyl- or 3-arylamino derivatives. The compounds with the primary amino group at the 3 position were best prepared by reaction of 3-chloroquinoline-2,4(1H,3H)-diones with in situ generated ammonia under anhydrous conditions. An alternative approach to the primary amines via reduction of 3-azidoquinoline-2,4(1H,3H)-diones was investigated. The reduction of 3-azidoquinoline-2,4(1H,3H)-diones with zinc in acetic acid gave moderate to good yields of the desired products, while the reaction with triphenylphosphane afforded exclusively 4-hydroxyquinoline-2(1H)-ones.