Sodium Hydroxide → 2-Amino-5-methoxybenzenesulfonamide

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Reaction Steps

A solution of 7-methoxy-1,1-dioxo-1,4-dihydro-2H-1λ6-benzo[1,2,4]thiadiazin-3-one (Example 2a, 15 g, 65.7 mmol) in a 50% aqueous sulfuric acid solution (140 mL) was heated at 130° C. for 6 h. The solution was then poured over ice and neutralized at 0° C. with the addition of saturated aqueous sodium hydroxide solution. The mixture was then extracted with ethyl acetate. The organic phase was washed with brine, and dried over magnesium sulfate, filtered and dried in vacuo to afford the desired product, 2-amino-5-methoxy-benzenesulfonamide (8.1 g, 40.1 mmol, 61% yield) as a brown solid. See procedure described in Girard, Y., et al., J. Chem. Soc. Perkin Trans 1, 1043-1047 (1979). 1H NMR (400 MHz, DMSO -d6): δ 3.65 (s, 3H), 5.40 (s, 2H), 6.73 (d, 1H, J=8.8 Hz), 6.90 (dd, 1H, J1=8.8 Hz, J2=2.8 Hz), 7.07 (d, 1H, J=2.8 Hz), 7.19 (s, 2H).

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