反应详情

温度

80 °C

To a solution of 3-hexylthiophene-2-carboxaldehyde (7.8 g, 40 mmol) in pyridine/ethanol (60 mL, 1/1, v/v) was added hydroxylamine hydrochloride salt (4.2 g, 60 mmol). The solution was stirred with refluxing at 80° C. overnight. After cooling, the solution was rotary evaporated to remove the solvent. The residue was taken up with chloroform (100 mL) and the resulting solution was washed twice with distilled water (50 mL), dried over anhydrous magnesium sulfate, and rotary evaporated to remove the solvent. The viscous liquid residue was then dissolved in acetic anhydride (30 mL) containing 0.2 g of potassium acetate, and the resulting mixture was refluxed at 140° C. for 3 h. After cooling down to room temperature, the solution was poured into 100 mL H2O and extracted three times with hexanes (50 mL). The organic extracts were combined and washed until neutral, dried over anhydrous magnesium sulfate, and rotary evaporated to remove the solvent. The yellow liquid residue was subjected to silica-gel column chromatography (EtOAc/Hex=8/92, v/v, Rf=0.4) to yield a light yellow liquid product (5.0 g, 65% yield). 1H NMR (400 MHz, acetone-d6) δ (ppm): 7.85 (d, 1H, J=5.2 Hz); 7.19 (d, 1H, J=5.2 Hz); 2.80 (t, 2H, J=7.8 Hz); 1.68 (m, 2H); 1.28-1.38 (m, 6 H); 0.88 (m, 3H).

1. temperatureAfter cooling
2. customthe solution was rotary evaporated
3. customto remove the solvent
4. washthe resulting solution was washed twice with distilled water (50 mL)
5. dry with materialdried over anhydrous magnesium sulfate
6. customrotary evaporated
7. customto remove the solvent
8. dissolutionThe viscous liquid residue was then dissolved in acetic anhydride (30 mL)
9. additioncontaining 0.2 g of potassium acetate
10. temperaturethe resulting mixture was refluxed at 140° C. for 3 h
11. temperatureAfter cooling down to room temperature
12. additionthe solution was poured into 100 mL H2O
13. extractionextracted three times with hexanes (50 mL)
14. washwashed until neutral,
15. dry with materialdried over anhydrous magnesium sulfate
16. customrotary evaporated
17. customto remove the solvent