Sulfuric Acid → 1H-Pyrrolo[3,2-f]quinoline-1,2(3H)-dione

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Reaction Steps

To a 1 L flask was added sodium sulfate (0.6 mol) and water (100 mL) and the mixture was stirred until the solids dissolved. To this solution was added a solution of 6-aminoquinoline (0.033 mol) in 1N aqueous hydrochloric acid (50 mL) and ethanol (10 mL). The mixture was stirred and chloral (0.036 mol) was added. To the resulting solution was added a solution of hydroxylamine hydrochloride (0.108 mmol) in water (30 mL). This mixture was then heated to gentle reflux until all the solids dissolved and was then heated for a further 15 min. The flask was removed from the heat and the solution was poured onto ice (500 g) with stirring. The resulting solid was collected by filtration, washed with water and air dried to give N-quinolin-6-yl-2-hydroxyiminoacatamide (94%). To a 1L, 3 necked flask was added concentrated sulfuric acid (100 mL). The acid was stirred and heated to 100 C. N-Quinolin-6-yl-2-hydroxyiminoacatamide (45 mmol) was added slowly and the resulting solution was heated for 1 h. The reaction mixture was carefully poured onto ice/water (750 mL) and stirred for about 1 h. The solids were collected by filtration, washed with water and air dried to give the desired compound, (46%).

Provenance & Evidence