反应详情

Et3N (123 mL, 93.6 mmol) was added to a solution of 5-ethyl-2-pivalamidopyridine 1-oxide (16.0 g, 72.0 mmol) in POCl3 (250 mL) and the reaction mixture was heated at reflux for 3 days. Excess POCl3 was distilled off and the residue was poured into water. The mixture was neutralized with aqueous NaOH to pH 9. The aqueous layer was extracted with ethyl acetate. The organic layer was dried over MgSO4 and the solvent was evaporated in vacuo. The residue was purified by chromatography on silica gel (10% EtOAc in petroleum ether) to afford N-(6-chloro-5-ethylpyridin-2-yl)pivalamide (900 mg, 5%) and unreacted 5-ethyl-2-pivalamidopyridine 1-oxide (4.8 g). 1H NMR (CDCl3, 300 MHz) δ 8.12 (d, J=8.7, 1H), 7.94 (br s, 1H), 7.56 (d, J=8.7, 1H), 2.70 (q, J=7.5, 2H), 1.30 (s, 9H), 1.23 (t, J=7.5, 3H).

1. temperaturethe reaction mixture was heated
2. temperatureat reflux for 3 days
3. distillationExcess POCl3 was distilled off
4. additionthe residue was poured into water
5. extractionThe aqueous layer was extracted with ethyl acetate
6. dry with materialThe organic layer was dried over MgSO4
7. customthe solvent was evaporated in vacuo
8. customThe residue was purified by chromatography on silica gel (10% EtOAc in petroleum ether)