Sodium Sulfite → HCID 178518956, compound

Temperature

0 °C

To a mixture of 3-bromo-2-carboxyaniline (6.6 g, 30.6 mmol, see Aust. J. Chem., 1999, 52, 1061) in H2O (28 ml) and HCl (conc., 6 ml) was added a solution of NaNO2 (2.11 g, 30 mmol) in H2O (5 ml) at 0° C. The mixture was stirred at 0° C. for 30 minutes then a solution of Na2SO3 (10.4 g, 82.5 mmol) in H2O (28 ml) was added slowly. The mixture was stirred at room temperature for 2 hours and HCl (conc., 9 ml) was slowly added. The resulting mixture was stirred at room temperature for additional 18 hours, then at 80° C. for 4 hours, and finally cooled to room temperature. The reaction mixture was basified to dissolve the precipitate and then reacidified. The precipitated 4-Bromo-1H-indazol-3-ol CLXXXIII was filtered and dried in vacuo (yellow powder, 3.19 g, 49% yield).

1. stirringThe mixture was stirred at room temperature for 2 hours
2. stirringThe resulting mixture was stirred at room temperature for additional 18 hours
3. waitat 80° C. for 4 hours
4. temperaturefinally cooled to room temperature
5. dissolutionto dissolve the precipitate
6. filtrationThe precipitated 4-Bromo-1H-indazol-3-ol CLXXXIII was filtered
7. customdried in vacuo (yellow powder, 3.19 g, 49% yield)

ORD record

ord-bf14a856c4104ba7a1e0dd3454d00cd6

Source dataset

uspto-grants-2008_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07446118B2