The hydrolysis of 4-chloro-3-quinolinesulfonyl chloride (1) gives 4-ch
loro-3-quinolinesulfonic acid (2) or 1,4-dihydro-4-oxo-3-quinolinesulf
onic acid (3). Compound (2) reacts with primary and secondary aliphati
c or primary aromatic amines to give 4-amino-3-quinolinesulfonic acids
(4). Desulfonation of quinolinesulfonic acids (2,3,4) yields 4(1H)-qu
inolinone or 4-aminoquinolines (5).