2-[6-(4-Benzyloxy-butyl)-benzoimidazol-1-yl]-4-(3-chloro-phenyl)-thiazole-5-carboxylic acid ethyl ester → 4-(3-Chloro-phenyl)-2-[6-(4-hydroxy-butyl)-benzoimidazol-1-yl]-thiazole-5-carboxylic acid ethyl ester

Participants

Reaction Steps

To a mixture of 0.434 g (0.795 mmole) of 2-[6-(4-benzyloxy-butyl)-benzoimidazol-1-yl]-4-(3-chloro-phenyl)-thiazole-5-carboxylic acid ethyl ester (I.41c) and 5 mL of acetonitrile at 0 degrees was added dropwise 0.836 mL (0.795 mmole) of boron trifluoride-dimethyl sulfide complex. The mixture was stirred at ambient temperature for 2 hours and then concentrated under reduced pressure. Saturated sodium bicarbonate was added to the residue and the mixture was extracted three times with 15 mL of dichloromethane. The combined organic layers were washed with brine, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue was purified by silica gel chromatography, eluting with methanol-dichloromethane (gradient 0:100-3:97) to give 0.266 g of 4-(3-chloro-phenyl)-2-[6-(4-hydroxy-butyl)-benzoimidazol-1-yl]-thiazole-5-carboxylic acid ethyl ester (I.41d) as a white solid.

Provenance & Evidence