Reaction #10754

Reaction equation

3-Benzo[b]thiophen-2-yl-2-hydroxy-4-methoxy-benzaldehyde

potassium carbonate

Methyl iodide

→

3-benzo[b]thiophen-2-yl-2,4-dimethoxy-benzaldehyde

Yield 97.1%

Solvents

acetone

Conditions

Workup

1. 1
   Temperaturethe solution was heated
2. 2
   Temperatureto reflux for 3.5 h
3. 3
   TemperatureAfter cooling
4. 4
   Otherthe crude reaction
5. 5
   workup.ADDITIONmix
6. 6
   Concentrationwas concentrated on the rotavap
7. 7
   workup.ADDITIONmix of saturated, aqueous NH4Cl to water
8. 8
   Extractionextracted with EtOAc (2×15 mL)
9. 9
   DryingThe organic phase was dried over sodium sulfate
10. 10
    Filtrationfiltered
11. 11
    Concentrationconcentrated

Procedure

Ex-44B: 3-Benzo[b]thiophen-2-yl-2-hydroxy-4-methoxy-benzaldehyde (Ex-44A, 57.4 mg, 0.202 mmol) was dissolved in acetone (5 mL) and potassium carbonate (31 mg, 0.22 mmol) was added. Methyl iodide (25 uL, 0.40 mmol) was added and the solution was heated to reflux for 3.5 h. After cooling, the crude reaction mix was concentrated on the rotavap. The resulting residue was taken up in 10 mL of a 1:9 mix of saturated, aqueous NH4Cl to water and extracted with EtOAc (2×15 mL). The organic phase was dried over sodium sulfate, filtered, and concentrated to provide 58.5 mg of 3-benzo[b]thiophen-2-yl-2,4-dimethoxy-benzaldehyde as an orange, oily residue which was used without further purification, 97% yield. 1H-NMR (CDCl3) δ 10.31 (s, 1H), 7.92 (d, J=9 Hz, 1H), 7.81–7.88 (m, 2H), 7.56 (d, 1H), 7.33–7.39 (m, 2H), 6.88 (d, J=9 Hz, 1H), 3.91 (s, 3H), 3.64 (s, 3H).

Source