Sulfuric Acid → HCID 178507166, compound

Participants

Reaction Conditions

Reaction Steps

A mixture, which is cooled to 0° C., of 3,7-diamino-2-phenyl-2,5-dihydro-4H-pyrazolo[4,3-c]quinolin-4-one (100 mg), concentrated sulfuric acid (0.7 ml) and water (4 ml) was added dropwise a solution of sodium nitrite (46 mg) in water (1 ml), stirred at 0° C. for 30 minutes, at 90° C. for 1 hour and at room temperature for one night. The reaction mixture was neturalized by adding 5% sodium hydrogen carbonate, and ethyl acetate and methanol were added thereto. The insoluble materials were filtered off. The filtrate was extracted with ethyl acetate. The extract was washed with water and brine, dried over anhydrous magnesium sulfate and then the solvent was distilled off under reduced pressure. The residue was purified with silica gel column chromatography to obtain the target compound (18 mg).

Provenance & Evidence