Boron tribromide → Ammonia

Participants

Reaction Steps

Boron tribromide (1M in dichloromethane, 10.1 mL, 1.224 mmol) was added to an ice-cooled solution of the product of example 75 (140 mg, 0.286 mmol) in dichloromethane (4 mL) and the mixture was stirred at room temperature for 2 hours. The reaction was quenched with 0.88 ammonia solution and stirred at room temperature for 16 hours. The reaction mixture was adjusted to pH 8 by dropwise addition of 2N hydrochloric acid (aq) and extracted with dichloromethane (2×10 mL). The combined organic layers were dried over sodium sulfate and concentrated in vacuo. Purification of the residue by column chromatography on silica gel, eluting with dichloromethane:methanol:0.88 ammonia, 95:5:0.5, afforded the title compound as a pale yellow foam in 15% yield, 20 mg.

Provenance & Evidence