Water → 1H-Indazole-5-sulfonic acid (1-hydroxy-1,3-dihydro-benzo[c][1,2]oxaborol-6-yl)-amide

Beteiligte Stoffe

Reaktionsschritte

To a solution of 6-amino-3H-benzo[c][1,2]oxaborol-1-ol (0.385 g, 2.07 mmol) in anhydrous pyridine (30 mL) at 5° C. was added 1H-indazole-5-sulfonyl chloride (0.45 g, 2.07 mmol) and the resulting orange solution stirred at room temperature for 0.5 h. The reaction was warmed to 50° C. for 2 h and then the pyridine was removed under reduced pressure to afford a sticky residue. This was treated with water (40 mL) and sonicated for 5 h at 70° C. The fine precipitate that formed was collected by filtration, washed with water and dried in vacuo generating 0.402 g (59%) of the title compound as a yellowish orange solid. mp 222° C.; 1H NMR (400 MHz, DMSO-d6) δ (ppm): 10.21 (s, 1H), 9.19 (s, 1H), 8.24 (s, 2H), 7.67 (s, 2H), 7.48 (d, J=1.2 Hz, 1H), 7.22 (d, J=8.0 Hz, 1H), 7.17 (dd, J=8.2, 2.0 Hz, 1H), 4.84 (s, 2H); MS (ESI) m/z=330 (M+1, positive); HPLC purity: 97.30% (MaxPlot 200-400 nm), 97.30% (220 nm).

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