反应详情

Heat a mixture of 2-chloro-5-trifluoromethylpyridine-N-oxide (40 g, 202.5 mmol) and POCl3 (200 mL) to 80° C. and stir for 16 hours. After cooling to room temperature, remove the excess POCl3 under vacuum. Pour the residue into ice water, and neutralize the mixture to pH=7 with solid NaHCO3. Extract the resulting mixture with diethyl ether (3×80 mL), dry the combined ether extracts (Na2SO4), filter, and evaporate to give a brown oil. Purification by column chromatography affords the title product as pale yellow solid. 1H NMR (400 MHz, CDCl3) δ 7.97 (d, 1H), 7.41 (d, 1H).

1. temperatureHeat
2. customremove the excess POCl3 under vacuum
3. additionPour the residue into ice water, and neutralize the mixture to pH=7 with solid NaHCO3
4. extractionExtract the resulting mixture with diethyl ether (3×80 mL)
5. dry with materialdry the combined ether
6. filtrationfilter
7. customevaporate
8. customto give a brown oil
9. customPurification by column chromatography