Hydrochloric Acid → 4-Iodo-2-(quinoxaline-5-sulfonylamino)benzoic acid

Participants

Reaction Steps

A mixture of 2-amino-4-iodo-benzoic acid (10 g, 38 mmol, 1.0 equiv.) and quinoxaline-5-sulfonyl chloride (8.7 g, 38 mmol) in 100 mL of water was basified with satd. aq. Na2CO3, with stirring, to adjust the pH to 8.0. As the reaction progressed, the pH was maintained at 8.0±0.2 by adding satd. aq. Na2CO3. After 3 h, no further pH changes were observed. The reaction mixture was stirred at rt for another 16 h. Conc. HCl was added to adjust the pH to <2. The precipitated solid was collected by filtration, washed with water and dried to afford the title compound as white solid (17 g, 37.4 mmol, 98%). MS (ESI+): calcd. for C15H10IN3O4S, 455.0; m/z found, 456 [M+H]+. 1H NMR (500 MHz, DMSO-d6): 14.0 (br s, 1H), 11.6 (s, 1H), 9.10 (d, J=1.5, 1H), 9.97 (d, J=1.5, 1H), 8.60 (d, J=7.4, 1H), 8.42 (d, J=8.4, 1H), 8.06 (t, J=7.5, 1H), 7.95 (d, J=1.2, 1H), 7.51 (d, J=8.3, 1H), 7.37 (dd, J=8.3, 1.2, 1H).

Provenance & Evidence