1,1'-Carbonyldiimidazole → HCID 86673410, compound

Participants

Reaction Steps

(±)-tert-Butyl (1R,2R)-1-(6-bromopyridin-2-yl)-2-hydroxy-2-phenylethylcarbamate (1.1 g, 1.40 mmol) was dissolved in trifluoroacetic acid (25% in dichloromethane, 25 mL) and stirred at room temperature for 1 h. The reaction was concentrated, dissolved in methanol, and loaded onto a strong cation exchange cartridge. The cartridge was flushed with several volumes of methanol which were discarded. The product was eluted with 2M ammonia in methanol and concentrated. The resulting residue was suspended in tetrahydrofuran (25 mL), cooled to 0° C., and treated with carbonyldiimidazole (580 mg, 3.58 mmol) in a single portion. The resulting suspension was stirred at 0° C. for 5 min. The ice bath was removed and stirring continued for 1 h. The reaction was treated with an additional portion of carbonyldiimidazole (90 mg) and stirred at room temperature for 2 h. The reaction was quenched by addition of 2M ammonia in methanol and concentrated. The resulting residue was purified by column chromatography (25%-->50% EtOAc/Hex) to give nearly pure product. The material was further purified by trituration of the solid with diethyl ether. 1H-NMR (CDCl3, 500 MHz) δ 7.65 (dd, J=7.6, 7.6, 1H), 7.52 (d, J=7.6, 1H), 7.37-7.50 (m, 6H), 6.83 (bs, 1H), 5.63 (d, J=5.5, 1H), 4.92 (d, J=5.5, 1H). 13C-NMR (CDCl3, 126 MHz) δ 159.9, 159.2, 142.6, 139.7, 138.2, 129.13, 129.08, 128.2, 125.8, 119.6, 83.6, 64.4. Mass spec.: 319.1 (MH)+.

Provenance & Evidence