Method I: Synthesis of 2-amino-4-chlorobenzamide (ii-b)
1. 2-Amino-4-chlorobenzoic acid (3.42 g, 20 mmol) was dissolved in DMF (45 mL) and HOBt (2.70 g, 20 mmol) was added.
2. After stirring for 10 min, EDC-HCl (3.82 g, 20 mmol) was added to the mixture.
3. the reaction mixture was stirred at room temperature for 2 hr.
4. NH4OH (28%, 5 mL) was slowly added at 0 °C with vigorous stirring.
5. After addition, continue stirring at room temperature for 2 hours.
6. The reaction mixture was added slowly dropwise to water (200 mL) and a precipitate was precipitated.
7. The precipitate was collected by filtration and dried under vacuum to give 2.98 g of the target product ii-b as a gray solid in 87.6% yield. 8.
8. The product was characterized by LCMS m/z = 171.0 (M + 1), 173.0 (M + 3) (Method B) (retention time = 1.39 min).
1H NMR (400 MHz, DMSO-d6): δ 7.27 (d, J = 9.6 Hz, 1H), 6.68 (d, J = 2.4 Hz, 1H), 6.60 (dd, J = 8.4, 2.0 Hz, 1H), 5.50-5.82 (m, 4H).
