反应详情

To a stirred solution of 4-chloro-pyridine-3-carboxylic acid ethyl ester (4.30 g, 23.2 mmol) in dry tetrahydrofuran (45 ml) is added potassium tert-butoxide (3.12 g, 27.9 mmol) portion wise at 0° C., followed by the addition of methyl 3-mercaptopropanoate (3.35 g, 27.9 mmol). The reaction mixture is stirred at RT for 2 h. After completion of the reaction, the solvent is distilled off and the residue is diluted with water (30 ml). The aqueous layer is extracted with EtOAc (3×40 ml). The combined organic layers are washed with water (40 ml), brine (40 ml), dried over anhydrous sodium sulfate and evaporated to get the crude product, which is purified by column chromatography (silica gel, 30% EtOAc/hexane) to get 4-(2-methoxycarbonyl-ethylsulfanyl)-pyridine-3-carboxylic acid ethyl ester (3.0 g, 11.2 mmol, 48%).

1. customAfter completion of the reaction
2. distillationthe solvent is distilled off
3. additionthe residue is diluted with water (30 ml)
4. extractionThe aqueous layer is extracted with EtOAc (3×40 ml)
5. washThe combined organic layers are washed with water (40 ml), brine (40 ml)
6. dry with materialdried over anhydrous sodium sulfate
7. customevaporated
8. customto get the crude product, which
9. customis purified by column chromatography (silica gel, 30% EtOAc/hexane)