Synthesis
Example 1 Preparation of 4-iodo-3-nitrobenzoic acid (Compound V): 45 g (0.25 mol) of 4-amino-3-nitrobenzoic acid, 400 mL of deionized water and 100 mL of concentrated hydrochloric acid were added to a reaction flask. Stirring was turned on and the reaction mixture was cooled to 0 to 5 °C before 50 mL of an aqueous solution containing 25.9 g (0.38 mol) of sodium nitrite was slowly added dropwise. Gradual dissolution of the solid was observed. After the dropwise addition was completed, the reaction was maintained at 0 to 5°C and continued for 1 hour. Subsequently, 200 mL of an aqueous solution containing 88 g (0.5 mol) of potassium iodide was slowly added dropwise at the same temperature. After completion of the dropwise addition, the reaction mixture was stirred at room temperature for 2 hours, during which time a solid precipitated. The solid product was collected by filtration, washed with deionized water and dried to give 65 g (0.22 mol) of 4-iodo-3-nitrobenzoic acid (compound V) in 89.7% yield.
References
[1] Patent: US2013/225810, 2013, A1. Location in patent: Paragraph 0081; 0082
[2] Tetrahedron, 2005, vol. 61, # 42, p. 10113 - 10121
[3] Tetrahedron Letters, 1997, vol. 38, # 46, p. 7963 - 7966
[4] Patent: WO2005/40157, 2005, A2. Location in patent: Page/Page column 67-68
[5] Patent: WO2010/62171, 2010, A2. Location in patent: Page/Page column 140
