2-Amino-5-nitrobenzenesulfonamide → 2,5-Diaminobenzenesulfonamide

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Reaction Steps

A mixture of 2-amino-5-nitrobenzenesulfonamide (Example 17b, 10 g, 46.08 mmol), 10% palladium on charcoal (˜1 g) in tetrahydrofuran (250 mL) was hydrogenated for 26 h at 25° C. under 1 atmosphere of hydrogen gas via balloon. The mixture was then filtered through Celite, washed with tetrahydrofuran, and the solvent removed in vacuo to afford the desired product. The catalyst/Celite mixture was slurried in methanol (400 mL) for 16 h, filtered and the solvent was removed in vacuo to afford a second batch of the desired product, 2,5-diaminobenzenesulfonamide (combined: 7.79 g, 41.65 mmol, 90.4% yield) as a light-brown solid. 1H NMR (400 MHz, DMSO-d6) δ: 4.54 (2H, bs), 4.98 (2H, bs), 6.55-6.60 (2H, m), 6.87 (1H, d, J=2.2 Hz), 6.99 (2H, bs). LC-MS (ESI) calcd for C6H9N3O2S 187.04, found 188.3 [M+H+].

Provenance & Evidence