反应详情

To the solution of 2,2-dimethyl-[1,3]dioxane-5,5-dicarboxylic acid diethyl ester (19.75 g, 75.96 mmol) in dimethyl sulfoxide (80 ml) was added sodium chloride (4.4 g, 75.76 mmol) and water (2 ml). The reaction was refluxed for 7 h. After such time, it was poured into saturated sodium chloride solution (500 ml) and extracted with ether (4×200 ml). The combined organics were washed with water, dried over sodium sulfate, filtered and concentrated in vacuo. The residual oil was distilled under reduced pressure. Three fractions collected between 100° C. and 120° C. were combined to afford 2,2-dimethyl-[1,3]dioxane-5-carboxylic acid ethyl ester (7.58 g, 53%) as a clear oil (J. Org. Chem. 1986, 51, 2637) 1H NMR (300 MHz, CDCl3) δ ppm 1.26 (t, J=7.1 Hz, 3H, CH3), 1.41 (s, 3H, CH3), 1.44 (s, 3H, CH3), 2.74-2.85 (m, 1H, CH), 3.96-4.30 (m, 6H, 3×OCH2).

1. temperatureThe reaction was refluxed for 7 h
2. extractionextracted with ether (4×200 ml)
3. washThe combined organics were washed with water
4. dry with materialdried over sodium sulfate
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. distillationThe residual oil was distilled under reduced pressure
8. customThree fractions collected between 100° C. and 120° C.