Trifluoroacetic acid → 6-Hydroxy-2-[4-(2-methoxy-2-oxoethoxy)phenyl]-3-[3-methoxy-4-(1-pyrrolidinylmethyl)benzyl]benzo[b]thiophene

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Reaction Steps

6-Benzyloxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl 3-methoxy-4-(1-pyrrolidinylmethyl)phenyl ketone (2.75 g, 5.0 mmol) in THF (25 mL) was treated with lithium aluminum hydride (420 mg) at 0° C. for 2 h, then quenched with water (1 mL) and sodium hydroxide (1.0 M, 3 mL). Stirring was continued for 45 min. The reaction mixture was diluted with brine (100 mL) and extracted with dichloromethane (100 mL×3). The combined organic layers were dried with sodium sulfate and concentrated in vacuo to give a white foam-like material. This material was dissolved in dichloromethane (50 mL), treated with triethylsilane (6.0 mL) and trifluroacetic acid (5.0 mL) at 0° C. for 2 h, and concentrated under reduced pressure. The residue was extracted with dichloromethane (100 mL×3) which was washed with saturated aqueous sodium bicarbonate (100 mL). The combined organic layers were dried with sodium sulfate and concentrated. Chromatography with Et3N:MeOH:EtOAc (5:5:90) afforded the product as a white solid (2.1 g, 78%).

Provenance & Evidence