Phosphorus tribromide → 2-(Bromomethyl)-5-chlorobenzofuran

Temperature

0 °C

Compound 34 (160 mg, 0.89 mmol) was dissolved in EtOH (5 mL). NaBH4 (36 mg, 0.98 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. Solvent was evaporated off in-vacuo. The resulting crude alcohol residue was dissolved in toluene (5 mL) and the solution was cooled to 0° C. PBr3 (92 μL, 0.98 mmol) was added dropwise over 10 min. The 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 35 (128 mg, 57%) as an oil. 1H NMR (500 MHz, CDCl3): δ: 7.48 (1H, d, J=2.05 Hz, ArH), 7.37 (1H, d, J=8.70, ArH), 7.25 (1H, dd, J=8.80 & 2.05 Hz ArH), 6.68 (1H, s, ArH), 4.55 (2H, s, 2-CH2).

1. waitat room temperature for 1.5 h
2. customSolvent was evaporated off in-vacuo
3. dissolutionThe resulting crude alcohol residue was dissolved in toluene (5 mL)
4. temperaturethe solution was cooled to 0° C
5. customwas then brought up to room temperature
6. stirringstirred for 1 h
7. customThe solvent was evaporated off in-vacuo
8. custompurified by flash chromatography
9. washeluting with hexane/EtOAc (4:1)

ORD record

ord-b28dd2d624ca489cb9e5dfdd483d4037

Source dataset

uspto-grants-2012_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08283340B2