Carbon Tetrachloride → 4-[(R)-1-(3,5-Dichloro-4-fluoro-phenyl)-3-methyl-2-oxo-2,3-dihydro-1H-imidazo[1,2-a]imidazol-3-ylmethyl]-benzonitrile

Participants

Reaction Conditions

Reaction Steps

To a room temperature suspension of (R)-3-(4-cyano-phenyl)-N-(3,5-dichloro-4-fluoro-phenyl)-2-[3-(2,2-dimethoxy-ethyl)-ureido]-2-methyl-propionamide (62.6 g, 125.9 mmol), PPh3 (51.98 g, 198.17 mmol), and Et3N (29.35 mL, 210.6 mmol) in MeCN (250 mL) was added CCl4 (20.3 mL, 210.6 mmol) in one portion. The reaction was stirred for 2 h and then cooled to 0° C. To this solution was added p-toluenesulfonic acid monohydrate (37.7 g, 198.2 mmol) and the reaction was heated at 70° C. for 2 h. The volatiles were evaporated in vacuo, and the residue was diluted with isopropyl acetate (i-PrOAc) (500 mL) and water (500 mL). The water layer was removed and the organic layer was washed with aqueous Na2CO3 (5 wt %, 500 mL) and then aqueous NaCl (3 wt %, 500 mL). The organic layer was dried over Na2SO4 and concentrated in vacuo to give a semi-solid. A mixture of Heptane/i-PrOAc (150 mL, 80:20 heptane:i-PrOAc) was added causing precipitation of a solid. The resulting slurry was stirred overnight and then filtered. The filtrate was evaporated in vacuo to give a brown oil. The oil was re-processed using the same conditions 3 more times. The remaining brown oil from the filtrate was then purified by flash chromatography on silica gel (20-50% EtOAc/hexanes) to give 48.0 g of the title compounds as a white solid, m/z 415.7 [M+H]+.

Provenance & Evidence