反应详情

To a solution of ethyl 3,4-dihydroxybenzoate (500 mg), N,N-dimethylethanol-amine (565 μL), and triphenylphosphine (1.51 g) in methylene chloride (20 mL) is added dropwise diisopropyl azodicarboxylate (1.37 mL) under argon gas atmosphere and ice-cooling. The mixture is stirred at room temperature for 1 day. The reaction mixture is diluted with ethyl acetate, washed with water and treated with 10% HCl to transfer basic materials in ethyl acetate layer to the aqueous layer. The aqueous layer is neutralized with saturated aqueous sodium hydrogencarbonate and extracted with chloroform/methanol/tetrahydrofuran (4:1:1, ×2). The extract is dried over anhydrous sodium sulfate and concentrated in vacuo. The residue is purified by flash column chromatography on NH-silica gel (Solvent; n-hexane:ethyl acetate=1:1→chloroform:methanol=19:1) to give ethyl 4-[2-(dimethylamino)ethoxy]-3-hydroxy-benzoate (240 mg, yield; 35%) as oil. MS (APCI) m/z; 254 [M+H]+

1. temperatureice-cooling
2. washwashed with water
3. additiontreated with 10% HCl
4. extractionextracted with chloroform/methanol/tetrahydrofuran (4:1:1, ×2)
5. dry with materialThe extract is dried over anhydrous sodium sulfate
6. concentrationconcentrated in vacuo
7. customThe residue is purified by flash column chromatography on NH-silica gel (Solvent; n-hexane:ethyl acetate=1:1→chloroform:methanol=19:1)