反应详情

To a solution of 4-methoxymandelic acid (2.00 g, 10.978 mmol) in 55 mL of dioxane at 90° C. is added 2-trimethylsilylethyl-N,N-diisopropyl-pseudourea. The resulting solution is refluxed for about 8 hours. After cooling the mixture is diluted with 50 mL of ethyl acetate, filtered, washed with saturated aqueous sodium bicarbonate followed by brine, dried over magnesium sulfate, and concentrated. The resulting residue is chromatographed on silica gel (9/1 hexanes/ethyl acetate) to give the title compound as an oil: 2.24 g, 72% yield. 1H NMR (300 MHz, CDCl3): 7.32 (d, J=8.8, 2 H), 6.89 (d, J=8.8, 2 H), 5.08 (d, J=5.6, 1 H), 4.38-4.17 (m, 2 H), 3.81 (s, 3 H), 3.41 (d, J=5.6, 1 H), 0.96 (m, 2 H), 0.01 (s, 9 H).

1. temperatureThe resulting solution is refluxed for about 8 hours
2. temperatureAfter cooling the mixture
3. filtrationfiltered
4. washwashed with saturated aqueous sodium bicarbonate
5. dry with materialdried over magnesium sulfate
6. concentrationconcentrated
7. customThe resulting residue is chromatographed on silica gel (9/1 hexanes/ethyl acetate)