Yield:202865-63-2 88.5%

Reaction Conditions:

with hydroxyamino hydrochloride;anhydrous Sodium acetate in ethanol at 45; for 1 h;

Steps:

16.A A. Preparation of 3-bromo-4-fluorobenzaldehyde oxime

In a jar, 3-bromo-4-fluorobenzaldehyde (10.0 g, 49.3 mmol), hydroxylamine hydrochloride (4.5 g, 64.0 mmol) and anhydrous sodium acetate (8.1 g, 98.5 mmol) were dissolved in ethanol (100 mL) , 45 °C reaction 1h.After the reaction is completed, it is cooled to room temperature, filtered by suction, the filter cake is washed with ethanol (50 mL×3), the filtrates are combined, and the solvent is evaporated under reduced pressure.The residue was dissolved in ethyl acetate (100 mL), washed with pure water (100 mL×2), dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure to give 3-bromo-4-fluorobenzaldehyde oxime as a white solid 9.5 g. The yield was 88.5. %.

References:

CN107382892,2017,A Location in patent:Paragraph 0160; 0161