[NH2:1][C:2]1[CH:11]=[CH:10][C:9]2[N:8]=[CH:7][CH:6]=[CH:5][C:4]=2[C:3]=1[C:12](N)=[O:13].S(=O)(=O)(O)O.[OH-].[Na+].[C:22]([O-])(O)=[O:23].[Na+]>CO.O>[CH3:22][O:23][C:12]([C:3]1[C:4]2[CH:5]=[CH:6][CH:7]=[N:8][C:9]=2[CH:10]=[CH:11][C:2]=1[NH2:1])=[O:13]
To a solution of 2 g (10.68 mmol) of the above 6-amino-quinoline-5-carboxylic acid amide in 10.76 mL of absolute methanol is added 2.34 mL (42.73 mmol) of concentrated sulphuric acid. The reaction is stirred in a microwave during 13 minutes at 140° C. The reaction is repeated 6 times with flask opening after each run because of gas formation. The mixture is then cooled at 0° C. and water is added. The pH of the mixture is increased slowly to 6 with addition of an aqueous 6N NaOH solution. The pH is adjusted to 8 with a saturated aqueous solution of NaHCO3. The product is extracted with ethyl acetate (4 times) and the combined organic layers are dried on Na2SO4, filtrated and evaporated. After flash chromatography purification with heptane and ethyl acetate as eluants, 555 mg (26%) of a yellowish solid are obtained; LC/MS: 203/204 (M+H)+.
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