Synthesis
The general procedure for the synthesis of 2-amino-5-iodo-6-methylpyridine from 2-amino-6-methylpyridine is as follows: a mixture of 2-amino-6-methylpyridine (5.40 g), periodic acid (2.28 g), and iodine (5.00 g) was dissolved in a mixture of acetic acid (30 mL), water (6 mL), and sulfuric acid (0.9 mL), and heated to a reaction temperature of 80°C for 3 hr. . After the reaction was completed, the mixture was cooled to room temperature and slowly poured into 100 mL of 10% aqueous sodium bisulfite solution. The aqueous phase was extracted with ether (3 x 100 mL) and the organic phase was combined. The organic phase was washed sequentially with 10% sodium hydroxide solution, dried over anhydrous sodium sulfate, filtered and concentrated. Purification by column chromatography (eluent: ethyl acetate) gave a yellow liquid product. The liquid was further dried under a vacuum pump to induce crystallization to finally obtain 2-amino-5-iodo-6-methylpyridine (4.48 g, 38% yield). The physical properties of the product were as follows: 1H NMR (300 MHz, DMSO-d6) δ 7.60,6.09,6.05,2.38.
References
[1] Patent: WO2014/39484, 2014, A1. Location in patent: Page/Page column 50
[2] Journal of Medicinal Chemistry, 2007, vol. 50, # 25, p. 6383 - 6391
[3] Patent: US2002/7066, 2002, A1
[4] Tetrahedron Letters, 2001, vol. 42, # 23, p. 3795 - 3797
[5] Tetrahedron Letters, 2003, vol. 44, # 14, p. 2971 - 2973
