Iodine → 2-Chloro-6-(hydroxymethyl)-4-iodo-3-pyridinol

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Reaction Steps

C1 (11.6 g, 72.7 mmol) and NaHCO3 (18.3 g, 218 mmol) are added to 200 mL H2O. The mixture is stirred until homogeneous, the flask is placed in an ice bath, iodine (19.4 g, 76.3 mmol) is added, and the reaction is stirred over the weekend at rt. The pH of the mixture is adjusted to 3 with 2N NaHSO4, and the mixture is extracted with 4×50 mL EtOAc. The combined organic layer is dried over MgSO4, is filtered, and the filtrate is concentrated in vacuo to a yellow solid. The crude solid is washed with EtOAc to provide 2-chloro-6-(hydroxymethyl)-4-iodo-3-pyridinol (C2) as an off-white solid (62% yield), and the filtrate is concentrated to a small volume and is chromatographed over 250 g silica gel (230-400 mesh) eluting with 2.5:4.5:4:0.1 EtOAc/CH2Cl2/hexane/acetic acid to afford additional pure C2 (12% yield). MS (EI) for C6H5Cl/NO2, m/z: 285(M)+.

Provenance & Evidence