Carbon Dioxide → (R)-5-(4-bromo-benzyl)-7-(3,5-dichloro-phenyl)-5-methyl-6-oxo-6,7-dihydro-5H-imidazo[1,2-a]imidazole-3-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A solution of (R)-3-(4-bromo-benzyl)-1-(3,5-dichloro-phenyl)-5-iodo-3-methyl-1H-imidazo[1,2-a]imidazol-2-one (4.5 g, 7.8 mmol) in THF (50 mL) was cooled to −40° C. To this was slowly added isopropyl magnesium bromide (1M in THF, 15.6 mL, 15.6 mmol) over 30 min. The reaction mixture was stirred at −40° C. for 1 h and then CO2 gas passed through the solution for 1 h. The reaction mixture was concentrated under reduced pressure and diluted with water. The mixture was acidified with 1N HCl and extracted with CH2Cl2 (3×100 mL). The combined extracts were washed with water, brine and dried with MgSO4. The mixture was filtered and concentrated in vacuo. The residue was dissolved in toluene (40 mL) and hexane was added (100 mL). The resulting precipitate was filtered and washed with hexane to afford 2.6 g of (R)-5-(4-bromo-benzyl)-7-(3,5-dichloro-phenyl)-5-methyl-6-oxo-6,7-dihydro-5H-imidazo[1,2-a]imidazole-3-carboxylic acid as a purple solid, m/z 495.5 [M+]+.

Provenance & Evidence