5-fluoro-1-benzofuran-2-carbaldehyde

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Compound 13 (180 mg, 1.10 mmol) was dissolved in EtOH (12 mL). NaBH4 (45 mg, 1.21 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 was taken up in EtOAc and washed with water, brine and dried (MgSO4). The solvent was evaporated off in vacuo. The residue was adsorbed on silica gel and purified by flash chromatography, eluting with hexane/EtOAc (3:1) to give 14 (150 mg, 91%) as a white solid. 1H NMR (500 MHz, CDCl3): δ: 7.36 (1H, d, J=8.35 Hz, H-7), 7.19 (1H, d, J=7.80, H-4), 7.00 (1H, t, J=8.75H-6), 6.60 (1H, s, H-3), 4.75 (2H, s, CH2). at room temperature for 1.5 h Solvents were evaporated off in-vacuo washed with water, brine dried (MgSO4) The solvent was evaporated off in vacuo purified by flash chromatography eluting with hexane/EtOAc (3:1)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A stirred solution of 12 (300 mg, 4.0 mmol) in acetic acid (10 mL) was refluxed for 24 h. After cooling, the solution was evaporated to dryness. The crude product was adsorbed on silica gel and purified by flash chromatography, eluting with hexane/EtOAc (4:1) to give the 13 (180 mg, 94%) as a white solid, 1H NMR (500 MHz, CDCl3): δ: 9.89 (1H, s, CHO), 7.57 (2H, m, ArH), 7.41 (1H, d, J=7.20 Hz), 7.26 (1H, d, J=6.94 Hz, H-4). 13C NMR CDEPT 135, (500 MHz, CDCl3): δ: 179.74 (CHO), 117.73 (C-3), 117.25 (C-7), 113.81 (C-6), 108.68 (C-4). After cooling the solution was evaporated to dryness purified by flash chromatography eluting with hexane/EtOAc (4:1)