Preparation method of 2-amino-3-bromobenzamide_Kain Industrial Additive

Background and overview^[1]

2-Amino-3-bromobenzamide can be used as a pharmaceutical synthesis intermediate. If 2-amino-3-bromobenzamide is inhaled, move the patient to fresh air; if skin contact occurs, take off contaminated clothing, rinse the skin thoroughly with soap and water, and seek medical attention if you feel unwell; if In case of eye contact, separate eyelids, rinse with running water or saline, and seek medical attention immediately; if ingested, rinse mouth immediately, do not induce vomiting, and seek medical attention immediately.

Preparation^[1]

The preparation of 2-amino-3-bromobenzamide is as follows:

Method 1: To a solution of 2-amino-3-bromobenzoic acid (0.5g, 2.3mmol) in DMF (5mL) at room temperature was added hydroxybenzotriazole (0.46g, 3.0mmol), 1-ethyl 3-(3-Dimethylaminopropyl)carbodiimide (0.53g, 2.8mmol), ammonium chloride (0.5g, 9.7mmol) and diisopropylethylamine (1.7ml, 9.7mmol) ). The mixture was stirred with N2 and stirred for 6 hours. The mixture was poured into water and extracted with EtOAc (3 x 50 mL). The combined extracts were washed with brine (2 x 20 mL), dried over MgSO4, filtered, and concentrated under reduced pressure. The residue was treated with DCM (10 mL) to give a precipitate, which was collected by filtration and dried to give 2-amino-3-bromobenzamide as a pale pink solid (0.42 g, 84%). LCMS(ESI)m/z215/217(M+H)+.

Method 2: Reflux the mixture of 2-amino-3-iodobenzoic acid (1.12g) and thionyl chloride (3.11ml) for 1 hour. The mixture was cooled, concentrated and co-evaporated twice with toluene. The dichloromethane solution of the residue was added dropwise to 28% ammonia solution, and then the resulting powder was collected, washed with water and dried under vacuum to obtain 2-amino-3-bromobenzamide, mass (ESI): 239.1 (M+) + Na)