[NH2:1][C:2]1[C:11]([C:12]([O:14][CH3:15])=[O:13])=[C:10]2[C:5]([C:6]3[CH:18]=[CH:17][O:16][C:7]=3[CH:8]=[N:9]2)=[CH:4][CH:3]=1.[H][H]>O1CCOCC1.C(O)(=O)C.C(OCC)(=O)C.[OH-].[OH-].[Pd+2]>[NH2:1][C:2]1[C:11]([C:12]([O:14][CH3:15])=[O:13])=[C:10]2[C:5]([C:6]3[CH2:18][CH2:17][O:16][C:7]=3[CH:8]=[N:9]2)=[CH:4][CH:3]=1A solution of methyl 7-aminofuro[2,3-c]quinoline-6-carboxylate (Intermediate 24, 1.13 g) in a mixture of dioxane (5 mL) and acetic acid (5 mL) was treated under an atmosphere of nitrogen with palladium hydroxide on carbon (10%, 0.1 g). The nitrogen was replaced by hydrogen and the mixture was stirred under an atmosphere of hydrogen for 24 hours. The mixture was diluted with ethyl acetate and filtered through Celite and the filtrate was washed with 1M aqueous sodium hydroxide solution, dried (MgSO4) and filtered. The filtrate was evaporated to dryness and the residue was purified by chromatography on silica eluting with a mixture of methanol and ethyl acetate with a gradient of 0-10%. The isolated product was triturated with a mixture of ether and cyclohexane and the solid was collected by filtration to give methyl 7-amino-1,2-dihydrofuro[2,3-c]quinoline-6-carboxylate (0.666 g) as a yellow solid.
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