Methanesulfonyl chloride → Methanesulfonic acid (5R)-3-(3-fluoro-4-iodo-phenyl)-2-oxo-oxazolidin-5-ylmethyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of (5R)-3-(3-fluoro-4-iodophenyl)-5-hydroxymethyl-oxazolidin-2-one (1019, 269.6 g, 0.8 mol) in methylene chloride (CH2Cl2, 1200 mL) was treated with N,N-diisopropylethylamine (Hunig's base, DIEA, 206.8 g, 279 mL, 1.6 mol, 2.0 equiv) at 25° C., and the resulting mixture was cooled down to 0-5° C. before methanesulfonyl chloride (MsCl, 109.97 g, 74.3 mL, 0.96 mol, 1.2 equiv) was dropwise introduced into the reaction mixture at 0-5° C. under N2. The resulting reaction mixture was subsequently stirred at 0-5° C. for 1 h and then gradually warmed up to room temperature for 4 h under N2. When TLC and HPLC/MS showed that the reaction was complete, the reaction mixture was quenched with H2O (500 mL). The resulting mixture was then stirred at room temperature for 30 min. before being concentrated in vacuo to remove methylene chloride. When almost all of methylene chloride was removed in vacuo, the residue was then treated with H2O (1000 mL). The resulting slurry was stirred at room temperature for an additional 1 h. The solids were then collected by filtration, washed with H2O (2×500 mL), and dried in vacuo at 40° C. for 24 h to afford the crude, desired (5R)-methanesulfonic acid 3-(3-fluoro-4-iodophenyl)-2-oxo-oxazolidin-5-ylmethyl ester (1020, 290.0 g, 332.0 g theoretical, 87.3%) as off-white powders, which was found to be essentially pure and was directly used in the subsequent reactions without further purifications. For 1020: 1H NMR (300 MHz, DMSO-d6) δ 3.26 (s, 3H, OSO2CH3), 3.83 (dd, 1H, J=6.4, 9.2 Hz), 4.19 (t, 1H, J=5.4 Hz), 4.44-4.54 (m, 2H), 5.01-5.06 (m, 1H), 7.22 (dd, 1H, J=2.4, 8.7 Hz), 7.56 (dd, 1H, J=2.4, 8.7 Hz), 7.84 (dd, 1H, J=7.5, 8.7 Hz); C11H11FINO5S, LCMS (EI) m/e 416 (M++H).

Provenance & Evidence