反应详情

12-bromododecanoic acid (2.0 g, 7.16 mmol) was added to a solution of potassium hydroxide (1.61 g, 28.65 mmol) in methanol (30 mLs) and refluxed for 20 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 in 1% diethyl ether/0.3% formic acid/methylene chloride to yield 12-(methoxy)dodecanoic acid (640 mg, 39%): mp 45°-47° C.; 1H NMR (300 MHz, CDCl3) δ 1.20-1.45 (bm, 15H, methylene envelope), 1.51-1.69 (bm, 4H, 0--CH2 --CH2, CH2 --CH2 --COOH), 2.34 (t, 2H, J=7.4, CH2 --COOH), 3.34 (s, 3H, 0--CH3), 3.38 (t, 2H, J=6.7, 0--CH2), 10.99 (br, 1H, COOH); 13C NMR (75.4 MHz, CDCl3) δ 24.75, 26.16, 29.10, 29.27, 29.38, 29.44, 29.53, 34.12, 58.50, 72.97, 179.70; m/z 231 (M+H+).

1. temperaturerefluxed for 20 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 in 1% diethyl ether/0.3% formic acid/methylene chloride