Hydrochloric Acid → 2H-1,2,4-Benzothiadiazine-3-acetic acid, 7-[(methylsulfonyl)amino]-, 1,1-dioxide

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Reaction Conditions

Reaction Steps

N-(4-Methanesulfonylamino-2-sulfamoyl-phenyl)-malonamic acid ethyl ester (prepared as described in Example 1e, 9.55 g, 26.16 mmol) was dissolved in 8% aqueous sodium hydroxide solution (262 mL) and heated at 100° C. for 1.5 h. The reaction mixture was cooled to 0° C. and the solution was acidified by slowly adding 12.0 M aqueous hydrochloric acid solution until pH 1-2 was reached. A precipitate started to form and the suspension was allowed to stir for 30 min at 0° C. The precipitate was collected by vacuum filtration, washed with cold water, and dried under high vacuum to afford the desired product, (7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ6-benzo[1,2,4]thiadiazin-3-yl)-acetic acid (7.20 g, 21.621 mmol, 82.6%), as a pinkish solid. 1H NMR (400 MHz, DMSO-d6) δ: 3.03 (3H, s), 3.56 (2H, s), 7.33 (1H, d, J=9.1 Hz), 7.52-7.54 (2H, m), 10.09 (1H, s), 12.24 (1H, s), 13.02 (1H, bs). LC-MS (ESI) calcd for C10H11N3O6S2 333.01, found 334.1 [M+H+].

Provenance & Evidence