3-Chlorobenzaldehyde → 1-(3-chloro-phenyl)-2-(1-trityl-1H-imidazol-2-yl)-ethanol

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Reaction Conditions

Reaction Steps

To a stirred, cooled (−78° C., acetone/dry ice bath) solution of 2-methyl-1-tritylimidazole (1 g; CAS 23593-68-2) in tetrahydrofuran (THF) (15 ml) under an argon atmosphere was added pentamethyldiethylene-triamine (0.64 ml). n-butyllithium solution (2.0 ml; 1.6 M in hexanes) was then added dropwise over a period of 10 min. The reaction mixture soon turned to a dark red compact slurry. The mixture was then stirred at a temperature between −40° C. and −50° C. for 6 hours. After cooling again to −78° C., a solution of 3-chlorobenzaldehyde (0.86 g) in THF (5 ml) was added dropwise for 5 minutes. The mixture was stirred overnight, slowly warming up to room temperature. The clear yellow solution was diluted with ethyl acetate (30 ml) and washed with H2O. The aqueous phase was back extracted with ethyl acetate (EtOAc). The combined organics were washed with H2O and brine, dried over MgSO4, filtered and concentrated. The crude product was purified by column chromatography (silica gel; gradient CH2Cl2→CH2Cl2/methanol 92:8) to give 1-(3-chloro-phenyl)-2-(1-trityl-1H-imidazol-2-yl)-ethanol (1.04 g) as light yellow amorphous solid. MS (ISP): 243.3 ([Trt]+)

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