反应详情

11-bromoundecanoic acid (10.0 g, 37.7 mmol) was added to a solution of potassium hydroxide (24.3 g, 433 mmol) in methanol (280 mL) and refluxed for 5 hrs. After cooling and acidification with HCl, solvent was removed under reduced pressure. The sample was dissolved in ethyl acetate and extracted with water. The organic phase was dried over sodium sulfate, and the solvent removed under reduced pressure. The product was purified by silica column chromatography using increasing concentrations of ethyl acetate in hexanes for elution. The product eluted in 25% ethyl acetate in hexanes. Solvent was removed under reduced pressure to give 11-(methoxy)undecanoic acid (200 mg, 2.5%): mp 31-32° C.; 1H NMR (300 MHz, CDC13) δ 1.1-1.3 (bm, 12H, methylene envelope). 1.45-1.63 (bm. 4H, O-CH2 --CH2, CH2 --CH2 --COOH), 2.34 (t, 2H, J=7.3, CH2 --COOH), 3.45 (s, 3H, CH3), 3.50 (t, 2H, J=6.8, 0--CH2), 10.70 (br, COOH); 13C NMR (75.4 MHz, CDC13) δ 24.64, 26.00, 29.00, 29.16, 29.29, 29.40, 34.00, 58.23, 72.81, 179.17; m/z 216 (M+).

1. temperaturerefluxed for 5 hrs
2. temperatureAfter cooling
3. customacidification with HCl, solvent was removed under reduced pressure
4. dissolutionThe sample was dissolved in ethyl acetate
5. extractionextracted with water
6. dry with materialThe organic phase was dried over sodium sulfate
7. customthe solvent removed under reduced pressure
8. customThe product was purified by silica column chromatography
9. temperatureusing increasing concentrations of ethyl acetate in hexanes
10. washfor elution
11. washThe product eluted in 25% ethyl acetate in hexanes
12. customSolvent was removed under reduced pressure