反应详情

2,12-Dimethyl-7-oxo-2,12-di-p-tolyl-tridecanedioic acid diethyl ester (9.0 g, 17.24 mmol) was added to a homogenous solution of KOH (85%, 4.0 g, 60.34 mmol) in water (10 mL) and ethanol (30 mL). The reaction mixture was heated to reflux for 6 h. The ethanol was removed under reduced pressure. The residue was diluted with water (30 mL) and the solution was acidified with concd. HCl (12 mL) to pH 1, then extracted with CH2Cl2 (3×80 mL). The combined organic layers were washed with brine, dried over anhydrous Na2SO4, concentrated, and purified by flash chromatography (silica gel, ethyl acetate/hexanes=1/20, 1/10, 1/2) to furnish 2,12-dimethyl-7-oxo-2,12-di-p-tolyl-tridecanedioic acid (3.1 g, 38.8%) as a white solid. Mp.: 48-50° C. 1H NMR (300 MHz, CDCl3/TMS): δ (ppm) 9.69 (br, 2H), 7.22 (d, 4H, J=8.1), 7.12 (d, 4H, J=8.1), 2.36 (t, J=7.5 Hz, 4H), 2.31 (s, 6H), 1.98-1.80 (m, 4H), 1.56-1.44 (m, 4H), 1.51 (s, 6H), 1.24-1.15 (m, 4H). 13C NMR (75 MHz, CDCl3/TMS): δ (ppm) 211.63, 183.07, 140.40, 137.00, 129.58, 126.43, 50.02, 42.82, 39.10, 24.74, 24.50, 22.82, 21.39. HRMS (LSIMS, nba): Calcd. for C29H39O5 (MH+): 467.2797, found: 467.2785.

1. temperatureThe reaction mixture was heated
2. temperatureto reflux for 6 h
3. customThe ethanol was removed under reduced pressure
4. additionThe residue was diluted with water (30 mL)
5. extractionHCl (12 mL) to pH 1, then extracted with CH2Cl2 (3×80 mL)
6. washThe combined organic layers were washed with brine
7. dry with materialdried over anhydrous Na2SO4
8. concentrationconcentrated
9. custompurified by flash chromatography (silica gel, ethyl acetate/hexanes=1/20, 1/10, 1/2)