Methyl 2-((tert-butoxycarbonyl)amino)-3-nitrobenzoate → Methyl 3-amino-2-[(tert-butoxycarbonyl)amino]benzoate

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Reaction Steps

To a suspension of methyl 2-[(tert-butoxycarbonyl)amino]-3-nitrobenzoate (103 g, 348 mmol) in methanol (800 mL) was added 10% palladium on carbon (50% wet; 10 g), and the mixture was purged with hydrogen and stirred under balloon pressure hydrogen at room temperature for 5 hr. The catalyst was removed by filtration, and the filtrate was concentrated in vacuo. The residual solid was suspended in diisopropyl ether (300 mL), and the suspension was stirred at room temperature for 3 hr. The resulting solid was collected by filtration and washed with diisopropyl ether to give the title compound (42.0 g, 158 mmol, 45%). The mixture of the removed catalyst described above and a colorless solid (the title compound) was suspended in tetrahydrofuran (200 mL), and the suspension was stirred at room temperature for 30 minutes. The insoluble material (the catalyst) was removed by filtration, and the filtrate was concentrated in vacuo. The residual solid was suspended in diisopropyl ether (300 mL), and the suspension was refluxed for 30 min. The resulting solid was collected by filtration and washed with diisopropyl ether to give the title compound (33.9 g, 127 mmol, 36%) as a colorless solid. Total amount: 75.9 g, 285 mmol, 82%.

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