[Cl:1][C:2]1[CH:6]=[CH:5][NH:4][C:3]=1[C:7]([O:9][CH3:10])=[O:8].[H-].[Na+].[N+:13](C1C=C([N+]([O-])=O)C=CC=1ON)([O-])=O.Cl>[Na+].[Cl-].CCOCC.O1CCOCC1.CN(C=O)C>[ClH:1].[NH2:13][N:4]1[CH:5]=[CH:6][C:2]([Cl:1])=[C:3]1[C:7]([O:9][CH3:10])=[O:8]To a mixture of methyl 3-chloro-1H-pyrrole-2-carboxylate (2.50 g, 15.7 mmol) and DMF (10 mL) at 0° C. was added 60% sodium hydride (0.816 g, 20.4 mmol). After 15 min, O-(2,4-dinitrophenyl)hydroxylamine (3.74 g, 18.8 mmol) was added and the mixture was stirred at 0° C. for 1 hr before warming to RT. After 18 hrs, the mixture was diluted with 10% NaCl and extracted with EtOAc. The organic fractions were dried with sodium sulfate and purified by silica gel chromatography using 10-30% Hexanes:EtOAc to afford a crude, brown oil. The oil was taken up in Et2O and treated with 4 N HCl in dioxane. The resulting off-white precipitate was collected by filtration to afford methyl 1-amino-3-chloro-1H-pyrrole-2-carboxylate hydrochloride.
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