Yield: 74%

Reaction Conditions:

with bromine in ethanol at 0 - 20; for 72 h;

Steps:

Step 1 . Synthesis of compound (242)
To a solution of 2-amino-2-hydroxypyridine 241 (10.Og, 91 mmol) in absolute ethanol (50mL) at 0°C was dropwise added bromine (5.2ml, 102mmol) and the mixture was stirred at room temperature for 3 days. The solvent was removed under reduced pressure and low temperature. The residue was cooled to 0°C. AcOEt (1 00mL) was added and the mixture was stirred for 1 h. The suspension was filtered off (washing with AcOEt). The red-brown solid recovered was dried under reduced pressure leading to the expected product 242 (Yield: 74%, 18.2g).

References:

ANAGENESIS BIOTECHNOLOGIES S.A.S. WO2021/13712, 2021, A1 Location in patent:Page/Page column 154