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ChemicalBook CAS DataBase List 5-Bromo-2-chlorobenzoic acid
21739-92-4

5-Bromo-2-chlorobenzoic acid synthesis

10synthesis methods
4.7g (0.03 mol) of 2-chlorobenzoic acid, 40mL of concentrated sulfuric acid and 0.936g (0.012 mol) of sodium sulfide are sequentially added into a 250mL four-mouth bottle, stirred for 20 minutes at 30 ℃ until the solution is clear, then 5.334g N-bromosuccinimide (0.03 mol) is added, the reaction is continued for 10 minutes at 30 ℃, and then the solution is slowly poured into 80mL ice water bath for crystallization to obtain a crude product of the 5-bromo-2-chlorobenzoic acid. Add the filter cake into a 250mL four-mouth bottle, add 24mL methanol and 36mL water, heat to 60 ℃, naturally cool, and stir for crystallization. Filtration, washing with 20mL of 40% volume fraction aqueous methanol, and drying at 55 ℃ for 6 hours gave 6.001g of a white solid, yield: 85.0%.
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Yield:21739-92-4 99.9 g

Reaction Conditions:

with water;sodium hydroxide at 90; for 4 h;

Steps:

1-3

Add all the above-obtained 5-bromo-2-chlorobenzonitrile products to a mixed solution containing 1000ml of water and 72g (1.8mol, 1.8eq) of sodium hydroxide, slowly raise the temperature to 90°C in a hot water bath, and keep stirring for 4 hours (HPLC detection of 3-bromo-2-chlorobenzonitrile <1.0%), the second product system is obtained; then the hot water bath is removed, the temperature of the system is slowly cooled to 5±5°C through an ice-water bath, and 281.6g concentrated Hydrochloric acid (HCl about 2.7mol, 2.7eq), a large amount of white solids are generated in the system. After the dripping is completed, heat and stir for 3 hours to obtain the third product system; the third product system is suction filtered, and the obtained The filter cake was rinsed, then sucked dry, and then dried in a circulating oven at 40°C for 12 hours to obtain 5-bromo-2-chlorobenzoic acid product (white solid, about 200g) with a yield of 85.9% and HPLC purity Is 99.90%.The product of 5-bromo-2-chlorobenzoic acid was detected by 1HNMR, 13CNMR, and LC-MS, and the results were consistent with Example 1, which proved that the obtained white solid was 5-bromo-2-chlorobenzoic acid.

References:

CN113321577,2021,A Location in patent:Paragraph 0040-0041; 0044-0045; 0049; 0052-0054; 0057-0058

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