Synthesis
Step 2: Preparation of methyl 4-amino-2-hydroxybenzoate
In a 500 mL Parr reactor, methyl 2-hydroxy-4-nitrobenzoate (1.3 g, 6.59 mmol) was mixed with a suspension formed by 10% Pd/C catalyst (100 mg) in methanol (40 mL). The reaction mixture was shaken for 1 h under hydrogen atmosphere (30 psi). Upon completion of the reaction, the catalyst was removed by filtration through a diatomaceous earth pad and the filtrate was concentrated under reduced pressure. Methyl 4-amino-2-hydroxybenzoate was obtained as a yellow solid (1.08 g, 6.46 mmol, 98% yield). The product was analyzed by UPLC-MS showing 100% purity and the mass spectrum (MS/ESI+) showed a molecular ion peak [MH]+ of 167.9.
References
[1] ACS Catalysis, 2014, vol. 4, # 6, p. 1777 - 1782
[2] Bioorganic and Medicinal Chemistry Letters, 2003, vol. 13, # 20, p. 3597 - 3600
[3] Patent: US2014/155391, 2014, A1. Location in patent: Paragraph 0432; 0434
[4] Journal of the Chemical Society, 1949, p. 1498,1502
[5] Proceedings - Indian Academy of Sciences, Section A, 1950, vol. 32, p. 357,362
