反应详情

温度

0 °C

H-D-Tyr-O-me hydrochloride 2.1 (25 g, 107.7 mmol) is dissolved in methylene chloride (150 mL) and aqueous sodium bicarbonate (22 g in 150 mL water), and then cooled to 0° C. To this resulting solution benzyl chloroformate (20 g, 118 mmol) is slowly added. After complete addition, the resulting solution is warmed to room temperature, and is then stirred for 2 h. The organic phase is separated, dried over Na2SO4, and concentrated under reduced pressure, to give the crude carbamate 2.2 (35 g). The crude CBZ-Tyr-OMe product is dissolved in methylene chloride (300 mL) containing concentrated H2SO4. Isobutene is bubbled though the solution for 6 h. The reaction is then cooled to 0° C., and neutralized with saturated NaHCO3 aqueous solution. The organic phase is separated, dried, concentrated under reduced pressure, and purified by silica gel column chromatography to afford the tert-butyl ether 2.3 (25.7 g, 62%).

1. customIsobutene is bubbled though the solution for 6 h
2. customThe organic phase is separated
3. customdried
4. concentrationconcentrated under reduced pressure
5. custompurified by silica gel column chromatography