4-Chlorobenzaldehyde → ethyl 2-bromo-5-((4-chlorophenyl)(hydroxy)methyl)-1-isopropyl-1H-imidazole-4-carboxylate

Participants

Reaction Conditions

Reaction Steps

LDA (63 mL, 2M solution in THF, 126 mmol) was slowly (over 30 min) added to a solution of 2-bromo-1-isopropyl-1H-imidazole-4-carboxylic acid ethyl ester (intermediate A; 11.0 g, 42.1 mmol) in THF (200 mL) at −78° C. After 2 h at −78° C., a solution of 4-chlorobenzaldehyde (8.9 g, 63.2 mmol) in THF (10 mL) was slowly added and the reaction mixture was allowed to warm to −20° C. over 30 min. The reaction mixture was quenched at −20° C. with 6 ml of acetic acid, concentrated and taken up in EtOAc/water, extracted twice with EtOAc. The combined organic extracts were washed with water and brine, dried (Na2SO4) and concentrated. The crude material was purified by chromatography (hexane/EtOAc, 60:40) to afford an orange foam. This was treated with 100 ml of 10% Et2O/hexane overnight and the resulting solid was filtered and rinsed with hexane to give the title compound as a white solid. ESI-MS: 403.1 [M+H]+ (LC-MS 2); 1H-NMR (DMSO-d6, 400 MHz) δ ppm 0.90 (d, J=7.04 Hz, 3 H) 1.26 (t, J=7.04 Hz, 3 H) 1.45 (d, J=7.04 Hz, 3 H) 4.25 (qd, J=7.04, 3.13 Hz, 2 H) 4.69 (quin, J=7.04 Hz, 1 H) 6.73 (d, J=4.30 Hz, 1 H) 6.83 (d, J=4.30 Hz, 1 H) 7.27 (m, J=8.60 Hz, 2 H) 7.41 (m, J=8.60 Hz, 2 H); Rf=0.15 (hexane/EtOAc, 60:40)

Provenance & Evidence