反应详情

Concentrated aqueous ammonia (10 ml) was cooled to -10° C. and 3,4-dihydro-3,3,5-trimethoxy-4-chloro-2(5H)-furanone (2 g) was gradually added. The mixture was stirred at 0° C. for about 5 minutes, at the end of which time the excess ammonia was neutralized with HCl-saturated methanol, followed by distillation under reduced pressure. The residue was extracted with chloroform, the chloroform was distilled off, and the residual oil was dissolved in methanol-HCl-saturated methanol (20 ml) and refluxed for 1 hour. The reaction mixture was concentrated under reduced pressure and the residue was subjected to silica gel column chromatography using hexane-acetone (5:3) as the eluent. The active fractions were pooled and concentrated under reduced pressure to give crystals. Recrystallization from benzene yielded 3,3,5-trimethoxy-4-chloro-2-pyrrolidinone as crystals (1.12 g).

1. distillationfollowed by distillation under reduced pressure
2. extractionThe residue was extracted with chloroform
3. distillationthe chloroform was distilled off
4. dissolutionthe residual oil was dissolved in methanol-HCl-saturated methanol (20 ml)
5. temperaturerefluxed for 1 hour
6. concentrationThe reaction mixture was concentrated under reduced pressure
7. concentrationconcentrated under reduced pressure
8. customto give crystals
9. customRecrystallization from benzene