Synthesis
General procedure for the preparation of Example IV 3-amino-2-iodo-6-(trifluoromethyl)pyridine: 3.85 g (12.3 mmol) of silver sulfate was added to a 100 mL ethanol solution containing 2 g (12.3 mmol) of 5-amino-2-(trifluoromethyl)pyridine under stirring and room temperature conditions. Subsequently, 3.13 g of iodine was added to the reaction system and stirred continuously for 24 hours at room temperature. Upon completion of the reaction, the suspended solids in the reaction medium were removed by filtration and the filtrate was concentrated under reduced pressure. The concentrated residue was dissolved in 200 mL of dichloromethane, washed sequentially with 5% sodium hydroxide solution and water, and the organic phase was dried with magnesium sulfate. Finally, the dried organic phase was concentrated under reduced pressure to afford 3.42 g of the target product 3-amino-2-iodo-6-(trifluoromethyl)pyridine as a pink solid in 96% yield and with a melting point of 127 °C.
References
[1] Patent: US2008/200495, 2008, A1. Location in patent: Page/Page column 6
[2] Patent: US2008/125459, 2008, A1. Location in patent: Page/Page column 16
[3] Patent: US2009/42873, 2009, A1. Location in patent: Page/Page column 25
[4] Patent: US2010/41634, 2010, A1. Location in patent: Page/Page column 19-20
[5] Patent: WO2010/91310, 2010, A1. Location in patent: Page/Page column 142
