Synthesis
The general procedure for the synthesis of 4,5-diiodoimidazole from imidazole was as follows: a mixture of potassium iodide (KI, 29.3 g, 176.0 mmol) and iodine (I2, 22.4 g, 88.0 mmol) in water (60 mL) was added to a solution of 1H-imidazole (3.0 g, 44.1 mmol) dissolved in 2M sodium hydroxide (NaOH, 10.6 g, 264.5 mmol) solution. The reaction mixture was stirred at 20 °C for 3 h and subsequently neutralized by adjusting the pH to 7 with 6 M hydrochloric acid (HCl). The resulting solid product was collected by filtration and purified by recrystallization with ethanol to give the final 4,5-diiodoimidazole as an anhydrous solid (14.0 g, 99.0% yield). The melting point was 166-168 °C. 1H NMR (300 MHz, DMSO-d6) δ (ppm): 12.75 (broad peak, 1H), 7.8 (broad peak, 1H). Mass spectrum (EI) m/z: 320.8 [MH]+.
References
[1] European Journal of Medicinal Chemistry, 2017, vol. 140, p. 293 - 304
[2] Patent: CN107501272, 2017, A. Location in patent: Paragraph 0085; 0086; 0087; 0088
[3] Synlett, 2004, # 7, p. 1306 - 1308
[4] Advanced Synthesis and Catalysis, 2013, vol. 355, # 2-3, p. 499 - 507
[5] Advanced Synthesis and Catalysis, 2013, vol. 355, # 16, p. 3231 - 3243
