关于氨基保护的?邻苯二甲酸酐引入邻苯二甲酰基示例 P. Meffre, P. Durand., Org. Syn., 76, 123 Into a 2-L, round-bottomed flask fitted with a Dean-Stark apparatus, reflux condenser, and drying tube containing calcium chloride are placed L-methionine methyl ester hydrochloride (50.0 g, 0.25 mol), phthalic anhydride (37.1 g, 0.25 mol), triethylamine (100 mL, 0.72 mol), and toluene (1 L). The mixture is magnetically stirred and heated under reflux for 4.5 hr at which point approximately 4.5 mL of water has separated. The reaction mixture is allowed to cool to room temperature and the precipitated triethylamine hydrochloride (34 g) is collected by suction filtration. The filtrate is washed with four 300-mL portions of 1 N aqueous hydrochloric acid followed by three 300-mL portions of water. The organic layer is dried over magnesium sulfate , filtered, and the filtrate is concentrated under reduced pressure using a rotary evaporator. The residual oil is placed under reduced pressure for 12 hr at 0.1-0.5 mm, followed by trituration with 200 mL of pentane to give 59 g (80%) of product as a white solid after collection and drying at room temperature under reduced pressure (mp 37-40°C). mp 37-40°C,; 20 D −41.6° (CHCl3, c 1.49).查看更多
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