Preparation
A, in the reaction vessel being provided with agitator, thermometer, reflux condenser, Dropping funnel, add cerium chloride 0.16mol, 4-hydroxy 3-methoxybenzene ethanol solution 0.19mol, Klorvess Liquid 400-500ml, control mixing speed and exist 160-190rpm, rising solution temperature, to 60-65°C, is slowly added to 2-chloro-6-nitrobenzoyl acid solution 0.13mol, sulfurous acid Hydrogen potassium solution 200ml, raises mixing speed to 260-310rpm, back flow reaction 5-7h；
B, reduction solution temperature, to 15-19°C, separate out solid, filter, and add diammonium hydrogen citrate solution 150-in filtrate 180ml, concentrating under reduced pressure, separate out solid, filter, dehydrant is dehydrated, brine, and pyridine solution washs, ethyl acetate solution Middle recrystallization, obtains crystal 2-amino-6-chlorobenzoic acid (C7H6ClNO2).
Synthesis
In a 250 mL round-bottomed flask, 5 g (32.77 mmol, 1.0 eq.) of 2-amino-6-chlorobenzonitrile was dissolved in 50 mL of a 30% aqueous potassium hydroxide (KOH) solution, followed by the addition of 3 mL of hydrogen peroxide (H2O2). The mixture was reacted under reflux conditions overnight. Upon completion of the reaction, the reaction mixture was washed sequentially with ether and dichloromethane each, followed by acidification. The acidified mixture was extracted with dichloromethane and ethyl acetate, and after separating the organic layer, the organic layer was washed with saturated brine. The organic layer was dried over anhydrous sodium sulfate and filtered, and the filtrate was concentrated under reduced pressure to give 5.31 g (30.95 mmol, 94% yield) of 2-amino-6-chlorobenzoic acid as an orange solid.
References
[1] Patent: KR2017/74380, 2017, A. Location in patent: Paragraph 0175-0178
[2] Patent: US2018/105527, 2018, A1. Location in patent: Paragraph 0439-0441
