[CH3:1][O:2][C:3]([C:5]1[CH:16]=[CH:15][C:8]2[CH:9]=[C:10]([C:12](O)=[O:13])[O:11][C:7]=2[CH:6]=1)=[O:4].C[N:18](C(ON1N=NC2C=CC=NC1=2)=[N+](C)C)C.F[P-](F)(F)(F)(F)F.CCN(C(C)C)C(C)C.[NH4+].[Cl-]>CN(C=O)C.[Na+].[Cl-]>[NH2:18][C:12]([C:10]1[O:11][C:7]2[CH:6]=[C:5]([C:3]([O:2][CH3:1])=[O:4])[CH:16]=[CH:15][C:8]=2[CH:9]=1)=[O:13]
6-(Methoxycarbonyl)-1-benzofuran-2-carboxylic acid (220 mg, 1.0 mmol) is combined with HATU (570 mg, 1.5 mmol) in DMF (4 mL). The mixture is treated portionwise with DIEA (350 μL, 2.0 mmol) and NH4Cl (183 mg, 3.4 mmol) and stirred for 3 h. The mixture is diluted with saturated NaCl (50 mL) and extracted with EtOAc (3×20 mL). The combined organics are washed with 2N HCl (2×10 mL), followed by water (2×10 mL), saturated NaHCO3 (2×10 mL) and additional H2O (2×10 mL) then dried (Na2SO4) and concentrated to afford 177 mg (81%) of methyl 2-(aminocarbonyl)-1-benzofuran-6-carboxylate as an orange-brown solid. HRMS (FAB) calcd for C11H9NO4+H: 220.0610, found 220.0603 M+H)+.
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