5-Hydroxy-4-methoxy-2-nitrobenzoic acid is an important organic synthetic reagent or pharmaceutical intermediate, which can be used in the preparation of anticancer drug Gefitinib intermediate and targeted drug AZD3759 intermediate. It is also an antioxidant synthesised from alpha tocopherol. It has the effect of scavenging hydroxyl radicals and reactive oxygen species.5-Hydroxy-4-methoxy-2-nitrobenzoic acid is used as an antioxidant in food and cosmetics. The compound also reacts with linoleic acid to form phenolic products with antioxidant activity.
General procedure for the synthesis of 2-nitro-4-methoxy-5-hydroxybenzoic acid from methyl 4,5-dimethoxy-2-nitrobenzoate: 770 g (11.665 mol, 85% purity) of potassium hydroxide pellets were dissolved in 4000 mL of ice water. To this clarified solution was added 800 g (3.317 mol) of methyl 4,5-dimethoxy-2-nitrobenzoate (1), and the resulting green suspension was heated by reflux. During heating, the solution gradually changed to red color. Stirring was maintained and refluxed for about 4 h while the distilled 850 mL of methanol/water mixture was collected. The reaction process was confirmed by HPLC monitoring. Upon completion of the reaction, the solution was cooled to room temperature and the pH was adjusted to 9 with 337.6 g (5.566 mol) of glacial acetic acid.The nitro reduction and isolation steps of the product (2) were carried out with reference to Example 1. Finally 558.5 g (3.049 mol, 92% yield) of gray crystalline product was obtained.
[1] Patent: US2008/319194, 2008, A1. Location in patent: Page/Page column 5
[2] Journal of the Chemical Society, 1932, p. 1370,1375
[3] ChemMedChem, 2014, vol. 9, # 7, p. 1476 - 1487
[4] Patent: WO2018/119441, 2018, A1. Location in patent: Paragraph 00556; 00557
