Synthesis
The general procedure for the synthesis of 2-amino-4-methoxybenzoic acid from 4-methoxy-2-nitrobenzoic acid is as follows:
Intermediate 113: Synthesis of 2-amino-4-methoxybenzoic acid
4-Methoxy-2-nitrobenzoic acid (3 g, 16.4 mmol) was dissolved in methanol (80 mL) and 10% palladium carbon catalyst (300 mg) was added. The hydrogenation reaction was carried out at room temperature and atmospheric pressure for 18 hours. Upon completion of the reaction, the reaction mixture was filtered through diatomaceous earth to remove the catalyst and the filtrate was concentrated to dryness under reduced pressure to give 2.50 g (100% yield) of 2-amino-4-methoxybenzoic acid as a colorless solid.
1H NMR (DMSO-d6) δ: 3.70 (s, 3H); 6.09 (dd, 1H); 6.23 (d, 1H); 7.59 (d, 1H).
References
[1] Patent: WO2006/134378, 2006, A1. Location in patent: Page/Page column 112
[2] Patent: WO2010/123975, 2010, A1. Location in patent: Page/Page column 101-102
[3] Patent: US2013/281398, 2013, A1. Location in patent: Paragraph 0493; 0494
[4] Patent: US5599814, 1997, A
[5] Patent: WO2007/71963, 2007, A2. Location in patent: Page/Page column 52
