乙基 (2S)-2-(氧杂-2-基氧基)丙酸甲酯

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: In ethanol (450 ml) was dissolved ethyl(2S)-2-(3,4,5,6-tetrahydro-2H-pyran-2-yloxy)propionate, to which was added, under ice-cooling, 2N sodium hydroxide solution (150 ml), and the mixture was stirred for one hour at room temperature. The reaction mixture was cooled with ice, to which was added a 27° C. aqueous solution of acetic acid (100 ml), followed by extraction with dichloromethane (200 ml) three times. Dichloromethane layers were combined and washed with a saturated aqueous saline solution (100 ml) twice, followed by drying over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure to leave (2S)-2-(3,4,5,6-tetrahydro-2H-pyran-2-yloxy)propionic acid (29.5 g) as a colorless waxy product. to which was added, under ice- cooling The reaction mixture was cooled with ice, to which followed by extraction with dichloromethane (200 ml) three times washed with a saturated aqueous saline solution (100 ml) twice by drying over anhydrous magnesium sulfate The solvent was distilled off under reduced pressure

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: In dichloromethane (200 ml) was dissolved (S)-(-)-ethyl lactate (35.4 g), to which was added, under ice-cooling, p-toluenesulfonic acid.hydrate (570 mg). To the mixture was added dropwise 3,4-dihyro-2H-pyran (30.2 g), taking 30 minutes, followed by stirring for one hour under ice-cooling. To the reaction mixture was added a 5% aqueous solution of sodium hydrogen carbonate (50 ml), which was vigorously stirred, then the organic layer was separated. The organic layer was further washed with a 5% aqueous solution of sodium hydrogen carbonate and dried over anhydrous magnesium sulfate, then the solvent was distilled off under reduced pressure to afford ethyl(2S)-2-(3,4,5,6-tetrahydro-2H-pyran-2-yloxy)propionate (61 g) as a pale yellow oily product. to which was added, under ice- cooling cooling was vigorously stirred the organic layer was separated The organic layer was further washed with a 5% aqueous solution of sodium hydrogen carbonate dried over anhydrous magnesium sulfate the solvent was distilled off under reduced pressure