Iodine → Ethyl (6-fluoro-3-iodopyridin-2-yl)carbamate

Participants

Reaction Conditions

Reaction Steps

28.6 ml (0.18 mol) TMEDA was added to a solution of compound 56 (13.41 g, 72.9 mmol) dissolved in 300 ml anhydrous THF. The mixture was cooled to −78° C. (under N2). To the stirred reaction mixture was added 76 ml (2.5 M n-BuLi) and the mixture was stirred for 2 hours at −78° C. After the addition of I2 (48 g, 0.17 mol), the mixture was stirred for 1 hour at −78° C. The reaction mixture was subsequently quenched with a saturated Na2S2O3 solution and allowed to warm to ambient temperature. Ethyl acetate was added to the mixture and the organic layer was washed with a saturated NaHCO3 solution, dried (Na2SO4), filtered and concentrated. The resulting residue was purified by flash chromatography (diethyl ether/PE (1/3) to 1/1) and afforded (6-fluoro-3-iodo-pyridin-2yl)-carbamic acid ethyl ester (57) (amorphous, 15.86 g, 70%). 1H-NMR (400 MHz, CDCl3): δ 8.07 (bt, J=8 Hz, 1H), 7.24-7.14 (bs, 1H), 6.49 (dd, J=8 Hz, 3 Hz, 1H), 4.29 (q, J=8 Hz, 2H), 1.35 (t, J=8 Hz, 3H). (TLC diethyl ether/PE 1/1 Rf 0.27).

Provenance & Evidence