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[求助]
合成
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二硫醇二羟基乙酸和维生素E反应为什么要先加无水乙酸酐然后又除去？这篇文献里面的，没有看懂，求指导.《Programmed Hydrolysis in Designing Paclitaxel Prodrug for Nanocarrier Assembly》。 A solution of dithiodiglycolic acid (2 g, 11.0 mmol) and anhydrous acetic anhydride (30 mL) was stirred at 30 °C under nitrogen atmosphere for 2 h. Acetic anhydride was removed at room temperature under high vacuum with the addition of toluene three times. The residue was added to a mixed solution of dichloromethane (20 mL), VE (1.0 g, 2.3 mmol) and a catalytic amount of DMAP, and stirred for 5 min at room temperature. The product was purified by silica gel column chromatography, eluting with a solution of hexane, ethyl acetate and acetic acid. The eluting solvent was removed under vacuum to give 0.757 g of acid VE-S-S-COOH with a yield of 55.3%. The acid (0.5 g, 0.84 mmol) and dichloromethane (10 mL) were stirred in an ice water bath. DCC (0.198 g, 1.0 mmol) and DMAP (13.8 mg, 0.01 mmol) were added. The solution changed to a suspension. After 5 min, PTX (0.72 g,0.84 mmol) was added and the mixture was stirred for a further 2 h. After filtration to remove DCU, the solution was purified by silica gel column chromatography, eluting with a solution of chloroform and methanol (200:1) to obtain the target compound PTX-S-S-VE as white solid (0.814 g, yield: 67.7% ). The purity was 99.4%, analyzed by the HPLC method. 这是合成原文。就想了解一下这个乙酸酐的作用是什么。谢谢。如果是我理解错了，也请告知一下。谢谢。 |
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