[NH:1]1[C:5]2=[N:6][CH:7]=[CH:8][C:9]([O:10][C:11]3[CH:16]=[CH:15][C:14]([OH:17])=[CH:13][CH:12]=3)=[C:4]2[CH:3]=[CH:2]1.[N+:18]([O-])([OH:20])=[O:19]>CC(O)=O>[N+:18]([C:15]1[CH:16]=[C:11]([O:10][C:9]2[CH:8]=[CH:7][N:6]=[C:5]3[NH:1][CH:2]=[CH:3][C:4]=23)[CH:12]=[CH:13][C:14]=1[OH:17])([O-:20])=[O:19]4-(1H-Pyrrolo[2,3-b]pyridin-4-yloxy)phenol (Step b, 5.6 g, 24.8 mmol, 1.0 eq.) was dissolved into AcOH (100 ml) and HNO3 (70%, 2.4 mL, 26.7, 1.1 eq.) was added dropwise. The reaction was stirred for 1 h at RT. The acids were removed by evaporation and the residue was taken up in NaHCO3 (aq., saturated, 100 mL) and CH2Cl2 (200 mL). Separated the layers and washed the organic layers with NaHCO3 (aq., saturated, 50 mL) and brine (50 mL). Back extracted aqueous layers with CH2Cl2 (100 ml) and dried the combined organic layers over MgSO4, filtered and concentrated. Further purification by column chromatography (0-100% EtOAc/Hexane) yielded 2-nitro-4-(1H-pyrrolo[2,3-b]pyridin-4-yloxy)-phenol.
불러오는 중…