Hydroxyamine hydrochloride → 3-Hexylthiophene-2-carbonitrile

Temperatur

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).