Propargyl bromide → [1-(5-Bromomethyl-isoxazol-3-yl)-3-methyl-butyl]-carbamic acid t-butyl ester

Participants

Reaction Conditions

Reaction Steps

N-Chlorosuccinimide (5.80 g, 43.4 mmol, 1.00 equivalents), [1-(hydroxyimino-methyl)-3-methyl-butyl]-carbamic acid tert-butyl ester (10.00 g, 43.4 mmol, 1.00 equivalents) and pyridine (0.70 mL) were stirred in chloroform (70 mL) at room temperature for 1 hour. Propargyl bromide (4.83 mL, 54.3 mmol, 1.25 equivalents) was added and the reaction was heated to 45° C. Triethylamine (6.35 mL, 45.6 mmol, 1.05 equivalents) was added dropwise over 20 minutes at 45° C. The reaction was stirred for an additional 1 hour, then it was diluted with water (200 mL) and extracted with dichloromethane (2×200 mL). The combined organic extracts were washed with saturated sodium bicarbonate (2×200 mL) and brine (200 mL). The organic portion was dried over sodium sulfate. Evaporation of the solvent gave a brown residue that was chromatographed by flash chromatography on silica gel to give the title compound as a white solid (6.48 g, 43%). MS (CI) m/z 247.0 (M−99)

Provenance & Evidence