Synthesis
Step 2 of Scheme 13: Methyl 5-iodo-2-hydroxynicotinate (4.75 g, 17.1 mmol) was dissolved in trichlorophosphorus (50 mL) and heated to reflux for 24 hours. After completion of the reaction, the solvent was removed by rotary evaporator. The crude product was neutralized with saturated sodium bicarbonate solution and subsequently extracted with ether. The organic phase was dried over anhydrous magnesium sulfate, filtered and concentrated by rotary evaporator. The crude product was purified by silica gel column chromatography to afford 4.3 g (85% yield) of methyl 2-chloro-5-iodonicotinate using a hexane solution of 5% ethyl acetate as eluent. The physical and chemical properties of this compound have been documented in Journal of Organic Chemistry, 1989, vol. 54.
References
[1] Patent: US2005/203081, 2005, A1. Location in patent: Page/Page column 13; 33
[2] Journal of Medicinal Chemistry, 1993, vol. 36, # 18, p. 2676 - 2688
[3] Patent: US5250548, 1993, A
[4] Patent: WO2008/76425, 2008, A1. Location in patent: Page/Page column 54
[5] Patent: WO2008/130600, 2008, A2. Location in patent: Page/Page column 46
