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

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Reaction Conditions

Reaction Steps

n-Butyllithium (1.6M in hexanes, 22 mL, 35 mmol) was added dropwise to a stirred, cooled (−78° C.) solution of 1,1-dimethylethyl (6-chloro-3-pyridinyl)carbamate (Description 6, 2.68 g, 11.7 mmol) and N,N,N′,N′-tetramethylethylenediamine (5.3 mL, 4.1 g, 35 mmol) in ether (60 mL). The mixture was allowed to warm to −10° C. and stirred for 2 h. The mixture was cooled to −78° C. and a cooled (−10° C.) solution of iodine (6.0 g, 24 mmol) in ether (20 mL) was added dropwise. The mixture was allowed to warm to room temperature and stirred for 18 h. Saturated aqueous ammonium chloride was added and the mixture was extracted with ether. The combined organic fractions were washed with aqueous sodium metabisulfite (10%), dried (MgSO4) and the solvent was evaporated under reduced pressure. The residue was triturated with hexane and the solid was collected and dried in vacuo to give the title compound as a brown solid (2.3 g, 55%). 1H NMR (400 MHz, CDCl3) δ 8.94 (1H, s), 7.73 (1H, s), 6.64 (1H, br s), and 1.54 (9H, s).

Provenance & Evidence