Synthesis
General procedure for the synthesis of methyl 2-amino-4,5-dimethoxybenzoate from methyl 4,5-dimethoxy-2-nitrobenzoate: 1.9 g (7.2 mmol) of methyl 4,5-dimethoxy-2-nitrobenzoate and 0.2 g of palladium-carbon catalyst were added to a 100 mL round-bottomed flask and dissolved in 50 mL of methanol. Hydrogen was passed into the reaction system and the reaction mixture was stirred at room temperature for 24 hours. The reaction progress was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the brown solid catalyst was removed by filtration. The product was separated and purified by column chromatography (eluent ratio: petroleum ether:ethyl acetate = 10:1, V/V) to afford 1.51 g of the white solid target compound in 88.7% yield with a melting point of 91-93°C. The product was purified by column chromatography (eluent ratio: petroleum ether:ethyl acetate = 10:1, V/V).
References
[1] Patent: CN105037279, 2017, B. Location in patent: Paragraph 0047; 0048
[2] Bioorganic and Medicinal Chemistry Letters, 2014, vol. 24, # 18, p. 4455 - 4459
[3] Indian Journal of Chemistry, Section B: Organic Chemistry Including Medicinal Chemistry, 1995, vol. 34, # 10, p. 911 - 913
[4] Justus Liebigs Annalen der Chemie, 1896, vol. 293, p. 190
[5] Journal of the American Chemical Society, 1919, vol. 41, p. 2147
