Phosphorus tribromide → HCID 59603166, compound

Participants

Reaction Conditions

Reaction Steps

A stirred solution of 20 (350 mg, 1.30 mmol) in acetic acid (10 mL) was refluxed for 24 h. After cooling, the solution was evaporated to dryness. The crude product (300 mg) was dissolved in THF (5 mL). NaBH4 (78 mg, 2.02 mmol) was added portionwise at 0° C., with vigorous stirring. The suspension was stirred at 0° C. for 15 min and then at room temperature for 1.5 h. Solvents were evaporated off in-vacuo. The crude residue (260 mg) was dissolved in toluene (20 mL) and the solution was cooled to 0° C. PBr3 (135 μL, 1.44 mmol) was added dropwise over 15 min. The reaction mixture was then brought up to room temperature and stirred for 1 h. The solvent was evaporated off in-vacuo. The residue was adsorbed on silica gel and purified by flash chromatography, eluting with hexane/EtOAc (4:1) to give 21 (200 mg, 36%). 1H NMR (500 MHz, CDCl3): δ: 7.03 (1H, d, J=7.50 Hz, H-4), 6.88 (1H, t, J=9.80, H-5), 6.75 (1H, s, H-3), 4.69 (2H, s, 2-CH2), 2.54 (3H, s, CH3).

Provenance & Evidence