反应 #2200599

反应方程式

di-tert-butyl chloro[5-chloro-6-(methoxycarbonyl)-1-oxidopyridin-2-yl]malonate

trifluoroacetic acid

→

methyl 3-chloro-6-(chloromethyl)pyridine-2-carboxylate 1-oxide

收率 66.9%

溶剂

dichloromethane

反应条件

后处理

1. 1
   温度was refluxed for 2.5 hours
2. 2
   温度cooled
3. 3
   浓缩concentrated to dryness
4. 4
   温度the mixture heated
5. 5
   温度at reflux until carbon dioxide
6. 6
   workup.ADDITIONethyl ether added
7. 7
   其他The organic was separated
8. 8
   萃取extracted with ethyl acetate
9. 9
   干燥dried (MgSO4)
10. 10
    过滤filtered
11. 11
    浓缩concentrated to dryness
12. 12
    其他The crude product was purified by column chromatography (20-50% ethyl acetate in hexane)

实验过程

A mixture of di-tert-butyl chloro[5-chloro-6-(methoxycarbonyl)-1-oxidopyridin-2-yl]malonate (19.65 g, 45.0 mmol), trifluoroacetic acid (41 mL) and dichloromethane (82 mL) was refluxed for 2.5 hours, cooled and then concentrated to dryness. The crude residue was taken up in xylene and the mixture heated at reflux until carbon dioxide was no longer given off. The reaction mixture was then cooled to room temperature and ethyl ether added followed by a small amount of saturated NaHCO3 solution. The organic was separated and the aqueous layer was saturated with brine and extracted with ethyl acetate. The organic layers were combined, dried (MgSO4), filtered and concentrated to dryness. The crude product was purified by column chromatography (20-50% ethyl acetate in hexane) to give methyl 3-chloro-6-(chloromethyl)pyridine-2-carboxylate 1-oxide (7.11 g, 30.1 mmol) as a brown solid; 1H NMR (CDCl3): δ 7.60 (d, 2H), 7.40 (d, 2H), 4.80 (s, 2H), 4.00 (s, 3H).

来源