Cesium carbonate → HCID 86635435, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of (S)-5-(3-methanesulfonyloxy-pyrrolidine-1-sulfonyl)-1-methyl-1H-pyrrole-2-carboxylic acid methyl ester (Ex. 13b, 7.75 g, 21.2 mmol) and cesium carbonate (11.6 g, 31.8 mmol) in degassed MEK (85 mL) at 60° C. was added 2,6-di-tert-butyl-4-mercaptophenol (7.6 g, 31.8 mmol). The resulting solution was stirred at 60° C. for 3 h. Upon completion, as determined by HPLC, the reaction was diluted with H2O (200 mL) and Ethyl acetate (100 mL). The layers were cut and the aqueous layer was extracted with Ethyl acetate (3×100 mL). The combined organic cuts were washed with a saturated ammonium chloride solution (1×100 mL), a 50% aqueous brine solution (1×100 mL) and brine (1×100 mL), dried over Na2SO4, and concentrated under reduced pressure. Silica gel chromatography (Ethyl acetate:hexanes, 1:2) afforded 9.34 g (87%) of (R)-5-[3-(3,5-di-tert-butyl-4-hydroxy-phenylsulfanyl)-pyrrolidine-1-sulfonyl]-1-methyl-1H-pyrrole-2-carboxylic acid methyl ester as a white solid, mp 83-85° C. 1H-NMR (400 MHz, CDCl3): δ 7.23 (d, 1H, J=2.0 Hz), 7.21 (s, 2H), 7.17 (d, 1H, J=2.0 Hz), 5.30 (s, 1H), 3.97 (s, 3H), 3.84 (s, 3H), 3.59 (dd, 1H, J=10.4, 7.2 Hz), 3.47 (pentet, 1H, J=6.8 Hz), 3.28-3.39 (m, 2H), 3.10 (dd, 1H, J=10.4, 6.4 Hz), 2.12-2.20 (m, 1H), 1.75-1.84 (m, 1H), 1.42 (s, 18H). Anal. Calcd. for C25H36N2O5S2: C, 59.03; H, 7.13; N, 5.51; S, 12.61. Found: C, 59.63; H, 7.34; N, 5.39; S, 12.23.

Provenance & Evidence