Iodine → tert-Butyl (6-chloro-4-iodopyridin-3-yl)carbamate

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n-BuLi (52.4 mL, 0.12 mol, 2.5 M soln in hexanes) was added dropwise over 30 mins to a cooled −78° C. solution of (6-chloro-pyridin-3-yl)-carbamic acid tert-butyl ester (10.0 g, 43.7 mmol) and TMEDA (19.8 mL, 0.13 mol) dissolved in ether. The solution was warmed to −10° C., stirred for 2 hours and then recooled to −78° C. A solution of iodine (22.75 g, 90 mmol) in ether (100 mL) was added via an addition funnel and the reaction was warmed to room temperature and stirred for 16 hours. The reaction was quenched with sat NH4Cl and sodium thiosulfite was added. The mixture was stirred for 30 mins and then extracted with ether. The organic extracts were washed with sodium thiosulfite, dried over MgSO4, filtered and concentrated. Purification by silica gel chromatography (0% to 15% EtOAc in hexanes) gave the product (8.6 g, 56%). 1H NMR (300 MHz, CDCl3): δ 1.52 (s, 9 H), 6.58 (s, 1 H), 7.26 (d, J=8.6 Hz, 1 H), 7.96 (m, 1 H), 8.23 (d, J=2.8 Hz, 1 H).

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