The reaction of 6-chloro-4-oxo-1,2,3,4-tetrahydroquinoline (I) with propionic anhydride (II) or propionyl chloride (III) in pyridine gives 6-chloro-4-oxo-1-propionyl-1,2,3,4-tetrahydroquinoline (IV), which is then treated with hydroxylamine hydrochloride in refluxing pyridine.