Methyl 4-acetamido-5-chloro-2-methoxy-3-nitrobenzoate → Methyl 4-amino-5-chloro-2-methoxy-3-nitrobenzoate

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Reaction Steps

Compound 11 (6.2 g, 20.5 mmol) was dissolved in methanol (70 mL), H2SO4 concentrated (4 mL) was added and the solution heated to reflux for 9 h. After cooling to r.t., the mixture was poured into ice (600 mL) and the precipitate formed was collected by filtration. Drying under hv gave 5.0 g (94%) of 12 as a yellow solid. Data of 12: Rf 0.85 (hexane/EtOAc 1:4). 1H NMR (300 MHz, DMSO-d6): δ 3.77 (s, 6H), 6.85 (brs, 2H), 7.82 (s, 1H). 13C NMR (75 MHz, DMSO-d6): δ 52.80, 64.68, 110.40, 114.21, 133.80, 142.29, 153.60, 163.48. MS (ESI): m/z (rel intensity) 261 (100). HRMS (FAB): m/z calcd for C9H9N2O5Cl, 260.0200; found, 260.0197.

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