反应详情

To a mixture containing 2.0 g of methyl 5-iodo-1,2-dihydro-3-pyridinecarboxylate, 1.6 g of diethylaniline, 1.64 g of benzyltriethylammonium chloride and 3.6 ml of distilled phosphorus oxychloride in 100 ml of dry acetonitrile are added 15 drops of water. The mixture is heated under reflux for 18 hours. After cooling the reaction mixture to room temperature, the solvent is removed under reduced pressure and the residue taken up in methylene chloride and extracted with water. The organic solution is dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue is chromatographed on a column of flash silica gel using methylene chloride as the eluent. Evaporation of the eluent yields a pale yellowish solid which is recrystallized from aqueous ethanol to give 1.1 g (52%) of methyl 2-chloro-5-iodo-3-pyridinecarboxylate as a white solid: m.p. 73°-73.5° C.; NMR (80 MHz, CDCl3) delta 3.96 (s, 3H), 8.43 (d, 1H, J=2.3 Hz), 8.71 (d, 1H, J=2.3 Hz).

1. temperatureThe mixture is heated
2. temperatureunder reflux for 18 hours
3. customthe solvent is removed under reduced pressure
4. extractionextracted with water
5. dry with materialThe organic solution is dried over anhydrous sodium sulfate
6. concentrationconcentrated under reduced pressure
7. customThe residue is chromatographed on a column of flash silica gel
8. customEvaporation of the eluent
9. customyields a pale yellowish solid which
10. customis recrystallized from aqueous ethanol