Ethanol → 11-ethoxyundecanoic acid

Participants

Reaction Steps

11-bromoundecanoic acid (2.25 g, 8.47 mmol) was added to a solution of potassium hydroxide (2.15 g, 38.3 mmol) in absolute ethanol (20 mL) and refluxed for 7 hrs. After cooling and acidification with HCl, solvent was removed under reduced pressure to give a white solid. The sample was dissolved in ethyl acetate and extracted with water. The organic phase was dried over sodium sulfate, and the solvent was removed under reduced pressure. The product was purified by silica column chromatography in 1% diethyl ether/0.3% formic acid/methylene chloride. Solvent was removed under reduced pressure to yield 11-(ethoxy)undecanoic acid (680 mg, 35%): mp 44°-45.5° C.; 1H NMR (300 MHz, CDCl3) δ 1.20 (t, 3H, J=7.0, CH3), 1.24-1.40 (bm, 12H, methylene envelope), 1.52-1.68 (bm, 4H, O--CH2 --CH2 ; CH2 --CH2 --COOH), 2.34 (t, 2H, J=7.5, CH2 --COOH), 3.41 (t, 2H, J=6.8, 0--CH2 --CH2), 3.48 (g, 2H, J=7.0, 0--CH2 --CH3), 10.25 (br, 1H, COOH); 13C NMR (75.4 MHz, CDCL3) δ 15.27, 24.75, 26.23, 29.11, 29.26, 29.40, 29.55*, 29.80, 34.12, 66.06, 70.76, 179.71; m/z 231 (M+H+).

Provenance & Evidence