Yield:935534-46-6 67%

Reaction Conditions:

with boron tribromide in dichloromethane at -78 - 20; for 16 h;Inert atmosphere;

Steps:

63.1 Step 1: 6-bromo-2-fluoro-3-hydroxy-benzaldehyde

A solution of 6-bromo-2-fluoro-3-methoxy-benzaldehyde (2.0 g, 8.6 mmol) indichloromethane (45 mL) under a N2 balloon was cooled to -78 °C. Boron tribromide (10 mL of 1 M, 10 mmol) was added dropwise under N2 atmosphere. The reaction was stirred at room temperature for 16 hours. The mixture was cooled to 0 °C and the excess boron tribromide was quenched with saturated NaHCC solution. Water was added and the solution was extracted with dichloromethane (3x). The combined organic layers were washed with brine, dried over Na2SC>4, and filtered and concentrated in vacuo to provide 6-bromo-2-fluoro-3-hydroxy-benzaldehyde (1.26 g, 67%). ESI-MS m/z calc. 217.94, found 220.9 (M+2)+; retention time (Method A): 0.41 minutes (1 minute run).

References:

WO2019/14352,2019,A1 Location in patent:Paragraph 001063; 001064